THE MINERAL DIAMOND

To see our natural diamond specimens, see the diamond specimens pages.


Diamond is the ultimate gemstone, having few weaknesses and many strengths. It is well known that Diamond is the hardest substance found in nature, but few people realize that Diamond is four times harder than the next hardest natural mineral, corundum (sapphire and ruby). But even as hard as it is, it is not impervious. Diamond has four directions of cleavage, meaning that if it receives a sharp blow in one of these directions it can cleave, or split. A skilled diamond setter and/or jeweler will prevent any of these directions from being in a position to be struck while mounted in a jewelry piece.

As a gemstone, Diamond's single flaw (perfect cleavage) is far outdistanced by the sum of its positive qualities. It has a broad color range, high refraction, high dispersion (fire), very low reactivity to chemicals, rarity, and of course, extreme hardness and durability. Diamond is the April Birthstone.

In terms of it's physical properties, diamond is the ultimate mineral in several ways:
  • Hardness: Diamond is a perfect "10", defining the top of the hardness scale, and by absolute measures four times harder than sapphire (which is #9 on that scale).
  • Clarity: Diamond is transparent over a larger range of wavelengths (from the ultraviolet into the far infrared) than is any other solid or liquid substance - nothing else even comes close.
  • Thermal Conductivity: Diamond conducts heat better than anything - five times better than the second best element, Silver!
  • Melting Point: Diamond has the highest melting point (3820 degrees Kelvin)
  • Lattice Density: The atoms of Diamond are packed closer together than are the atoms of any other substance
  • Tensile Strength: Diamond has the highest tensile strength of any material, at 2.8 gigapascals. However, that does not quite translate into the strongest rope or cable, as diamond has cleavage planes which support crack propagation. The strongest ropes can likely be made from another carbon material, carbon nanotubes, as they should not suffer from the effects of cracks and break. Still, if a long, thin, perfect crystal of diamond could be manufactured, it would offer the highest possible pulling strength (in a straight line - don't try to tie it in a knot!)
  • Compressive Strength: Diamond was once thought to be the material most resistant to compression (the least compressible). It is the material that scientists use to create the greatest pressures when testing matter. However, the rare metal Osmium has recently been shown to be even less compressible (although it is not as hard as diamond). Diamond has a bulk modulus (reciprocal of compressibility) of 443 GigaPascals (GPa). The bulk modulus of the metal osmium has recently been found to be 476 GPa, about 7% greater than diamond.

Diamond is a polymorph of the element carbon. Graphite is another polymorph. The two share the same chemistry, carbon, but have very different structures and properties.

  • Diamond is hard, Graphite is soft (the "lead" of a pencil).
  • Diamond is an excellent electrical insulator, Graphite is a good conductor of electricity.
  • Diamond is the ultimate abrasive, Graphite is a very good lubricant.
  • Diamond is transparent, Graphite is opaque.
  • Diamond crystallizes in the Isometric system and graphite crystallizes in the hexagonal system.
  • Somewhat of a surprise is that at surface temperatures and pressures, Graphite is the stable form of carbon. In fact, all diamonds at or near the surface of the Earth are currently undergoing a transformation into Graphite. This reaction, fortunately, is extremely slow.

Other polymorphs of carbon include:

  • carbon nanotubes
  • buckyballs
  • graphene
These are described in more detail on the graphite page.

Diamonds are found in kimberlite pipes (the cores of certain volcanoes originating beneath thick plates of the Earth's crust), and in alluvial deposits resulting from the erosion of those pipes. Nanodiamonds are also found as presolar grains in meteorites, and presumably in asteroids and comets.

For natural diamond mineral specimens, see our diamond specimens page.

PHYSICAL CHARACTERISTICS:

  • Color is variable and tends toward pale yellows, browns, grays, and also white, blue, black, reddish, greenish and colorless.
  • Luster is adamantine to waxy.
  • Transparency crystals are transparent to translucent in rough crystals.
  • Crystal System is isometric; 4/m bar 3 2/m
  • Crystal Habits include isometric forms such as cubes and octahedrons, twinning is also seen.
  • Hardness is 10
  • Specific Gravity is 3.5 (above average)
  • Cleavage is perfect in 4 directions forming octahedrons.
  • Fracture is conchoidal.
  • Streak is white.
  • Associated Minerals are limited to those found in kimberlite rock, an ultramafic igneous rock composed mostly of olivine.
  • Other Characteristics: refractive index is 2.4 ( very high), dispersion is 0.044, fluorescent.
  • Notable Occurrences include South Africa and other localities throughout Africa, India, Brazil, Russia, Australia, and Arkansas.
  • Best Field Indicator is extreme hardness.
DIAMOND specimens:
(hover for more info)
DIAMOND specimen dia-1
$ 125.00
Dims: approx. 11mm x 9mm x 8mm
Wt: 9.3 ct
unknown
This is a green to greenish gray, slightly translucent, irregularly shaped specimen. The color varies, and one patch is nearly colorless, and another is brown. The luster is excellent and characteristic of Diamond cubes, although this specimen does not have a simple shape.
no photo
dia-1 ($125.00)
unknown
DIAMOND specimen dia-2
$ 140.00
Dims: approx. 12mm x 10mm x 8mm
Wt: 12.5 ct
unknown
This is a large, brown, barely translucent, somewhat irregular cube. Its best feature is its size!
no photo
dia-2 ($140.00)
unknown
DIAMOND specimen dia-4
$ 60.00
Dims: approx. 5mm x 5mm x 5mm
Wt: 1.70 ct
unknown
This is a slightly brownish yellow, translucent specimen that appears to be three distinct cubes that have intergrown.
no photo
dia-4 ($ 60.00)
unknown
DIAMOND specimen dia-5
$ 50.00
Dims: approx. 6mm x 5mm x 4mm
Wt: 1.45 ct
unknown
This is a nice, green, translucent, interpenetration twin of cubes. The color is good and the cubes are distinct. One corner of the primary cube is absent (but not broken or cleaved), leaving a nice flat surface as a natural base.
no photo
dia-5 ($ 50.00)
unknown
DIAMOND specimen dia-6
$ 45.00
Dims: approx. 6mm x 5mm x 5mm
Wt: 1.25 ct
unknown
This specimen is a yellow, nearly transparent octahedron, with an interesting triangular growth pattern on some of the faces. It is barely clear enough to show a couple of internal fractures. The octahedral shape is not perfect; the opposing ends are offset about 1mm, but still yielding a symetrical crystal.
no photo
dia-6 ($ 45.00)
unknown
DIAMOND specimen dia-32
$ 360.00
Dims: approx. 15mm x 11mm x 9mm
Wt: 12.20 ct
unknown
One of the larger Diamond specimens in our stock, this piece is made up of at least ten cubic and cubo-octahedral crystals that are intergrown. The largest is a cubo-octahedron that, if isolated, would measure 8 mm in all dimensions; it has very good form, but shows a small amount of damage. All have a uniform moderate gray coloration. The piece only shows a dim translucence around its edges, but has an adamantine luster.
no photo
dia-32 ($360.00)
unknown
DIAMOND specimen dia-49
$ 90.00
Dims: 0.3 x 0.3 x 0.3" (9 x 8 x 7 mm)
Wt: 3.70 ct
unknown (likely Russia)
Upon first glance, one may think that this specimen consists of a single large, warped Diamond crystal. However, close study will reveal that it is actually made up of three intergrown Diamond cubes. All of these have marginal form, as they are rather rounded and indistinct. They have a uniform, pale gray coloration and show a bright, adamantine luster. All are moderately to dimly translucent and cloudy. The specimen actually appears to have some visible damage, in the form of a scar on its surface.
no photo
dia-49 ($ 90.00)
unknown (likely Russia)
DIAMOND specimen dia-50
$ 80.00
Dims: 0.3 x 0.3 x 0.3" (8 x 7 x 7 mm)
Wt: 3.15 ct
unknown
This very busy little specimen consists of one large Diamond crystal that acts as a base for at least 4 smaller crystals that are intergrown with it. The large crystal shows some warped but definable cubic form, and has excellent patterning on 2 of its faces. The smaller crystals show extremely odd forms that do not seem to correspond to the cubic system- some of them appear to be oblong, and one appears to be tabular, and shows evidence of twinning! All of these show a more or less uniform dull yellow coloration and a bright, adamantine luster, and are moderately translucent.
no photo
dia-50 ($ 80.00)
unknown
DIAMOND specimen dia-51
$ 110.00
Dims: 0.4 x 0.3 x 0.3" (1.0 x 0.8 x 0.7 cm)
Wt: 4.25 ct
unknown
This specimen consists of at least 5 intergrown Diamond crystals. All of these show a slightly warped but definite cubic form and a moderately dark gray coloration. The specimen's luster is rather odd in that a substantial portion of it has a very dull, almost waxy luster, whereas the remaining majority shows the standard bright, adamantine luster that is expected of Diamonds. However, subtle flashes of that luster seem to filter through the dull patina if one looks at the specimen from certain angles. Together, the intergrown crystals render the specimen only dimly translucent.
no photo
dia-51 ($110.00)
unknown
DIAMOND specimen dia-52
$ 270.00
Dims: 0.5 x 0.5 x 0.4" (1.3 x 1.3 x 1.0 cm)
Wt: 10.9 ct
unknown, probably Russia
This impressive specimen appears to consist of many small Diamond crystals that are so intergrown that only a few of their faces can be determined on the specimen's surface. A few show a bit more detail, but none are exposed enough to be considered integral. The specimen has the standard adamantine luster and a gray color that is quite common for industrial- and specimen-grade Diamonds, and shows only dim translucence around its edges, even in halogen light.
no photo
dia-52 ($270.00)
unknown, probably Russia
DIAMOND specimen dia-53
$ 125.00
Dims: 0.5 x 0.4 x 0.3 cm
Wt: 0.45 ct
Mir Pipe, Shaka, Russia
Though quite small, this lovely Diamond specimen has excellent octahedral form. The octahedral shape is slightly warped and not quite symmetrical, but is obvious and shows well-defined edges and clean faces that show its classic adamantine luster. The Diamond itself has a pale brown "champagne" coloration and is transparent and quite clear; as far as I can tell, it contains only 3 or 4 small internal fractures and a single, tiny inclusion.
no photo
dia-53 ($125.00)
Mir Pipe, Shaka, Russia
DIAMOND specimen dia-54
$ 135.00
Dims: 5 x 5 x 5 mm
Wt: 0.60 ct
Mir Pipe, Sakha, eastern Siberia, Russia
This octahedral Diamond crystal has a few unusual traits. One half of it retains the traditional octahedral form, but the other half has that of the trisoctahedron, wherein each octahedral face is divided into three smaller faces and is slightly domed. I have not seen such an occurrence in a Diamond crystal before this one. The crystal is in excellent condition, showing little, if any damage, and has a good though slightly rounded form, with moderately well-defined edges and striated but clean faces that possess the standard adamantine luster. The crystal has a very pale brown color that jewelers might call "champagne", and is quite clear, though the striations on its surface provide considerable interference. Like all of our Diamond specimens, this one has no accompanying Kimberlite host rock.
no photo
dia-54 ($135.00)
Mir Pipe, Sakha, eastern Siberia, Russia
DIAMOND specimen dia-55
$ 125.00
Dims: 5 x 5 x 5 mm
Wt: 0.65 ct
Mir Pipe, Sakha, eastern Siberia, Russia
A single Diamond octahedron constitutes this specimen. It is in excellent condition, showing no visible human-induced damage, and it has moderately good form, with slightly rounded but still definable edges and heavily patterned and striated faces that possess the obligatory adamantine luster. Its color is pale brown and it is transparent, but its clarity is mostly spoiled due to internal fractures and at least 1 inclusion. Upon examination under a 15-power loupe, I saw something very interesting- there is either an included crystal or a series of internal fractures that create some refraction within this crystal. When viewed from one or two directions in front of a light source, one can see a small area inside the crystal that glows with a colorful iridescence. I believe that since it is visible from 2 different, non-opposing directions, maybe the iridescence is caused by an inclusion.
no photo
dia-55 ($125.00)
Mir Pipe, Sakha, eastern Siberia, Russia
DIAMOND specimen dia-56
$ 160.00
Dims: 6 x 4 x 3 mm
Wt: 0.70 ct
Mir Pipe, Sakha, eastern Siberia, Russia
Though this Diamond octahedron is not perfectly symmetrical, it still has exceptional crystal form, with well-defined edges and flat, smooth faces. Two opposing faces have some small growth patterns on them, but these are relatively minor, also.
no photo
dia-56 ($160.00)
Mir Pipe, Sakha, eastern Siberia, Russia
DIAMOND specimen dia-57
$ 400.00
Dims: 0.3 x 0.2 x 0.2" (0.8 x 0.5 x 0.5 mm)
Wt: 1.50 ct
Argyle Mine, Kimberly region, western Australia
This small specimen is one of the largest and most well-formed Diamond octahedrons that we have had available. It is in excellent condition, showing no human-induced damage, and has excellent form; some of its points are slightly rounded, but its edges are very well-defined, and its faces are exceptionally smooth and clean, possessing only faint patterning and the standard adamantine luster. Its color is a pale brown that might be called "champagne", and it is transparent and somewhat clear. It does contain several large internal fractures that run along cleavage planes and provide considerable interference, but the material shows no inclusions.
no photo
dia-57 ($400.00)
Argyle Mine, Kimberly region, western Australia
DIAMOND specimen dia-80
$ 300.00
Dims: 0.5 x 0.4 x 0.3" (1.2 x 1.1 x 0.8 cm)
Wt: 1 g
South Africa
This complex thumbnail piece consists of several rounded and warped Diamond octahedrons that have intergrown to form a cluster. The largest of these has a diameter of 0.3" (7 mm) and shows the only damage that I can see. All have a pale gray color and the standard adamantine luster, and are translucent- the largest shows a few spots of dim transparence. The crystals formed together in such a way that a tiny, natural hole extends through the cluster- it is unfortunately too small to put a chain through it. There is no host rock present, of course.
no photo
dia-80 ($300.00)
South Africa
DIAMOND specimen dia-81
$ 225.00
Dims: 0.4 x 0.3 x 0.1" (9 x 8 x 3 mm)
Wt: >1 g
South Africa
This specimen consists of a partial Diamond crystal that has a single face cut into it. This face has a reasonably good polish, though it shows some lining and even a slight angle. The other surfaces are either crystalline and heavily warped or rounded, or show fresh damage. The Diamond is nearly colorless, showing a faint brown discoloration, and is moderately transparent with many internal flaws. It has the classic adamantine luster on its natural surfaces.
no photo
dia-81 ($225.00)
South Africa
DIAMOND specimen dia-82
$ 200.00
Dims: 0.3 x 0.3 x 0.2" (8 x 8 x 4 mm)
Wt: >1 g
South Africa
Half of a partly cut Diamond crystal makes up this thumbnail piece. The cut surface shows obvious, curved saw marks but has a moderately good polish, enabling one to study the interior of the piece. The other faces, though rounded through stepping gradation, show a definite cubo-octahedral form that is heavily striated and shows the classic adamantine luster. The piece is transparent and dimly to moderately clear, containing many internal flaws and at least two solid inclusions that are rather interesting- one looks like a small, transparent Diamond shard, and the other, larger one is dark but actually appears to have a warped crystal form. Examination with a stereo microscope might yield more information.
no photo
dia-82 ($200.00)
South Africa
DIAMOND specimen dia-83
$ 175.00
Dims: 0.3 x 0.3 x 0.2" (8 x 7 x 4 cm)
Wt: >1 g
South Africa
This half of a bisected Diamond crystal is in fair condition, showing a small amount of chipping damage that occurred during the cutting process. I thought that it might possibly be the match for specimen # DIA-82, but close examination shows several differences. The natural surfaces show a cubo-octohedral form that is rounded through stepped gradation and the classic adamantine luster. The cut surface shows several slightly curved saw marks and a moderately good polish, revealing the transparent and fractured interior- this is rather odd, as its natural surface is completely translucent. The piece has a dull, gray-brown coloration.
no photo
dia-83 ($175.00)
South Africa
DIAMOND specimen dia-84
$ 144.00
Dims: (largest) 3 x 3 x 3 mm
Wt: >1 ct. total
South Africa
This item consists of 4 tiny Diamond crystals. All show excellent form- three of them are octahedrons and one is a flattened tetrahedron, having the appearance of a triangular tablet. All are colorless, transparent and moderately to very clear, containing internal fractures; one of the smaller octahedrons contains a single black inclusion. Each shows the classic adamantine luster, and of course there is no base or host rock present on any of them.
no photo
dia-84 ($144.00)
South Africa
DIAMOND specimen dia-85
$ 40.00
Dims: 0.3 x 0.2 x 0.2" (8 x 4 x 4 mm)
Wt: >1 g
Aikhal Mine, Yakutia, Siberia, Russia
This small Diamond crystal is in excellent condition, showing no damage, but has a very warped, elongated and apparently octahedral form. Its color is pale gray, its luster is adamantine, and it is only dimly transparent in a few areas.
no photo
dia-85 ($ 40.00)
Aikhal Mine, Yakutia, Siberia, Russia
DIAMOND specimen dia-86
$ 38.00
Dims: 0.3 x 0.2 x 0.1" (8 x 4 x 2 mm)
Wt: >1 g
Aikhal Mine, Yakutia, Siberia, Russia
This thumbnail piece consists of a single highly warped and flattened Diamond crystal. Though it is in excellent condition, it is impossible to tell exactly as what variation of the cubic form it started to grow- it actually looks like a tiny flint spearhead. The Diamond has a gray color and adamantine luster and is generally opaque, though a few patches of dim translucence are visible.
no photo
dia-86 ($ 38.00)
Aikhal Mine, Yakutia, Siberia, Russia
DIAMOND specimen dia-87
$ 36.00
Dims: 0.3 x 0.2 x 0.1" (7 x 4 x 3 mm)
Wt: >1 g
Aikhal Mine, Yakutia, Siberia, Russia
This very warped and elongated Diamond octahedron is in excellent condition, showing no damage. It is colorless, transparent and moderately clear, containing many inclusions and a few internal flaws, and has the standard adamantine luster.
no photo
dia-87 ($ 36.00)
Aikhal Mine, Yakutia, Siberia, Russia
DIAMOND specimen dia-88
$ 34.00
Dims: 0.3 x 0.2 x 0.1" (6 x 4 x 2 mm)
Wt: >1 g
Aikhal Mine, Yakutia, Siberia, Russia
This Diamond crystal is in fair condition, as a sizable chunk has been cleaved out of one area. Its octahedral(?) form is highly warped, being not only elongated but flattened. It is colorless, transparent and dimly to moderately clear, containing many black inclusions, and it has the standard adamantine luster.
no photo
dia-88 ($ 34.00)
Aikhal Mine, Yakutia, Siberia, Russia
DIAMOND specimen dia-89
$ 32.00
Dims: 0.3 x 0.2 x 0.1" (7 x 5 x 2 mm)
Wt: >1 g
Aikhal Mine, Yakutia, Siberia, Russia
Although this Diamond crystal is in excellent condition, its cube-based form is so warped and flattened that I cannot tell what its original form was supposed to be. Even so, the Diamond is colorless, transparent and dimly to moderately clear due to the presence of many tiny black inclusions. As with all Diamonds, it has an adamantine luster.
no photo
dia-89 ($ 32.00)
Aikhal Mine, Yakutia, Siberia, Russia
DIAMOND specimen dia-90
$ 34.00
Dims: 0.2 x 0.2 x 0.1" (6 x 5 x 4 mm)
Wt: >1 g
Argyle Mine, Western Australia, Australia
Though slightly warped, this Diamond crystal has reasonably good octahedral form. It shows damage in the form of a cleavage chip off of one corner, but this does not appear to fresh damage due to the rather dull luster on the cleavage surface. The crystal has a brown color and the standard adamantine luster, and is transparent and actually quite clear, containing only a few internal fractures and inclusions.
no photo
dia-90 ($ 34.00)
Argyle Mine, Western Australia, Australia
DIAMOND specimen dia-91
$ 34.00
Dims: 0.2 x 0.2 x 0.1" (5 x 5 x 4 mm)
Wt: >1 g
Argyle Mine, Western Australia, Australia
This Diamond crystal shows discernable but warped octahedral form and is in very good condition, showing no appreciable damage. It has a dull, pale brown color and an adamantine luster and is transparent and moderately clear, containing several internal fractures and inclusions.
no photo
dia-91 ($ 34.00)
Argyle Mine, Western Australia, Australia
DIAMOND specimen dia-92
$ 32.00
Dims: 0.2 x 0.2 x 0.1" (5 x 5 x 4 mm)
Wt: >1 g
Argyle Mine, Western Australia, Australia
This thumbnail piece consists of a single small Diamond octahedron that is in very good condition- the only visible damage appears to have occurred prior to mining. Its octahedral form is somewhat warped but easily discernable, and its brown color and adamantine luster are common for the specie. It is transparent and surprisingly clear.
no photo
dia-92 ($ 32.00)
Argyle Mine, Western Australia, Australia
DIAMOND specimen dia-93
$ 30.00
Dims: 0.2 x 0.2 x 0.1" (6 x 5 x 3 mm)
Wt: >1 g
Argyle Mine, Western Australia, Australia
This Diamond crystal is in good condition, showing considerable old damage and possibly a small amount of new damage. This damage has affected its octahedral form, which is still discernable, however. Its color is brown, its luster is adamantine, and it is transparent and moderately clear, containing a few internal fractures and perhaps a few inclusions.
no photo
dia-93 ($ 30.00)
Argyle Mine, Western Australia, Australia
DIAMOND specimen dia-94
$ 28.00
Dims: 0.2 x 0.2 x 0.2" (5 x 5 x 5 mm)
Wt: >1 g
Argyle Mine, Western Australia, Australia
This well-formed Diamond octahedron is in excellent condition, showing no appreciable damage. It has a pale gray color and the classic adamantine luster, and is mostly translucent, showing only patches of dim transparence between its internal fractures and inclusions.
no photo
dia-94 ($ 28.00)
Argyle Mine, Western Australia, Australia
DIAMOND specimen dia-95
$ 525.00
Dims:0.26x0.25x0.25" (0.68x0.67x0.65 cm)
Wt: 1.30 ct (0.26g)
Vaal River, Cape province, Republic of South Africa
This is an excellent octahedral diamond, nearly perfect in form. It is very transparent, revealing several black inclusions and internal fractures. While it looks silver at first glance, it is actually a pale green in color. A groove through one of the points suggest that it may actually be two intergrown crystals, or perhaps this is an artifact of start/stop crystal growth. Close examination under a loupe shows minor damage to one point and one edge, likely caused when its kimberlite host was crushed to extract it.
no photo
dia-95 ($525.00)
Vaal River, Cape province, Republic of South Africa
DIAMOND specimen dia-96
$ 240.00
Dims: 6.1 x 5.8 x 5.5mm
Wt: 0.9 ct (0.18g)
Birum River, Ghana, Africa
This is a fine octahedron crystal of diamond, and is mostly colorless and transparent. It has a few inclusions, the largest of which appears to be flat from some sides but round from others - it is difficult to be sure because of the multiple internal reflections and because it is nearly in the center of the crystal. From some angles, the presence of this inclusion makes the diamond appear golden in color. There are also a couple of internal fractures, which adds an interesting sparkle to the appearance. Since the diamond is otherwise clear, multiple reflections (often 4 or 8) of the inclusions and/or fractures are visible, giving a false impression of a "phantom crystal" inside, at least from some angles. A very nice specimen.
no photo
dia-96 ($240.00)
Birum River, Ghana, Africa
DIAMOND specimen dia-97
$ 200.00
Dims: 0.24x0.20x0.16" (0.6x0.5x0.4cm)
Wt: 2.62ct (0.52g)
Ikati Mine, North West Territories, Canada
This diamond comes from Canada's first diamond mine, the Ikati Mine, about 300 km north of Yellowknife. The diamond appears gray with a hint of green in color, and has a typical (and excellent) surface pattern and texture. It appears to be a single octahedral crystal, somewhat distorted in that one "point" is really a ridge, and it is not symetrical. When examined closely (bright lights and a loupe), the clarity of the crystal is apparent. It looks nearly opaque at first glance, but that is entirely due to the surface pattern, luster, and color. It is actually very transparent and only slightly colored on the inside, although I was able to see a large black inclusion and a single internal fracture that reflects a rainbow of colors. Usually, diamonds this clear are cut (at least a trial facet) before the inclusions are found.
no photo
dia-97 ($200.00)
Ikati Mine, North West Territories, Canada
DIAMOND specimen dia-98
$ 86.00
Dims: 0.20x0.16x0.16" (0.5x0.4x0.4cm)
Wt: 1.62ct (0.32g)
Ikati Mine, North West Territories, Canada
This diamond has a brownish-green color, is translucent, and has a typical diamond luster and texture. Its shape is a rounded cube, somewhat distorted and with a dome termination on one face. Another face (see the closeup image) has a stepped appearance.
no photo
dia-98 ($ 86.00)
Ikati Mine, North West Territories, Canada
DIAMOND specimen dia-100
$ 69.00
Dims: 0.30x0.26x0.24" (0.75x0.67x0.60cm)
Wt: 2.35ct (0.47g)
Mbuji-Mayi, Congo
This diamond specimen is an intergrown cluster of 4 or 5 crystals, the largest of which dominates, and gives it a distorted cube shape. That largest crystal is yellow, and all are translucent with a typical diamond luster. There is a pleasing growth pattern on the surface. And there is actually a spot of damage (unusual for nearly indestructable diamonds) - it appears that a crystal broke off, probably during the mining operation when the host kimberlite was crushed.
no photo
dia-100 ($ 69.00)
Mbuji-Mayi, Congo
DIAMOND specimen dia-101
$ 93.00
Dims: 0.38x0.24x0.22" (0.96x0.60x0.56cm)
Wt: 3.20ct (0.64g)
Mbuji-Mayi, Congo
This diamond specimen consists of two intergrown crystal, each of which is a slightly rounded cube. The color is a gray-green, the diamonds are translucent, and their luster and surface texture is excellent.
no photo
dia-101 ($ 93.00)
Mbuji-Mayi, Congo
DIAMOND specimen dia-102
$ 66.00
Dims: 0.31x0.24x0.23" (0.78x0.62x0.58cm)
Wt: 2.25ct (0.45g)
Mbuji-Mayi, Congo
This specimen consists of multiple intergrown diamond crystals, mostly distinguishable by subtle differences in color. The overall shape is rather like a baby's shoe. The cluster is nearly colorless, although the luster and barely colored crystals combine to give a gray appearance. I think that the crystals may be transparent, but the surface texture hides the interior, and it may be translucent. Actually, there is a dark inclusion that can be seen as a change in shading from different angles, also indicating a somewhat transparent interior. The luster is adamantine, but (except for the largest crystal) the surface texture is largely random.
no photo
dia-102 ($ 66.00)
Mbuji-Mayi, Congo
DIAMOND specimen dia-103
$ 40.00
Dims: 0.157x0.130x0.126" (4.0x3.3x3.2mm)
Wt: 0.75ct (0.15g)
Tschikapa, Kasai
This diamond specimen is a single cube, with a second small cubic crystal attached at one corner. Both are nearly colorless, having a slightly silvery appearance, and are translucent with an excellent vitreous luster. The surface texture has the rough pattern typical of natural diamonds. There is a tiny black inclusion visible on one of the faces.
no photo
dia-103 ($ 40.00)
Tschikapa, Kasai
DIAMOND specimen dia-104
$ 137.00
Dims: 0.362x0.307x0.280" (9.2x7.8x7.1mm)
Wt: 4.70ct (0.94g)
Mbuji-Mayi, Congo
This diamond cluster consists of at least a half-dozen distinct crystals, which individually appear to be slightly distorted octahedrons. The resulting shape is quite complex. Their color varies, too, mostly a gray, but some have a hint of green or brown, one appears white, and there is part of one exposed that is a dark silvery-gray. The really unusual thing about this specimen is that there is quite a bit of damage present (and it is difficult to damage a diamond). It appears that several additional crystals were part of the cluster, but broke off during the mining operation. There are two clean cleavage planes, plus two spots where other diamond crystals appear to have detached.
no photo
dia-104 ($137.00)
Mbuji-Mayi, Congo
DIAMOND specimen dia-105
$ 69.00
Dims: 0.30x0.28x0.22" (0.77x0.70x0.57cm)
Wt: 2.35ct (0.47g)
Mbuji-Mayi, Congo
This diamond crystal is from Mbuji-Mayi, Congo (formerly known as Bakwanga, Zaire). It is a cluster of many rounded crystals, which have distorted shapes not easily described. The color is gray, it is translucent, and the luster is vitreous. Overall, the cluster has a somewhat pyramidal shape, and from one angle it has a distinct heart shape.
no photo
dia-105 ($ 69.00)
Mbuji-Mayi, Congo
DIAMOND specimen dia-106
$ 42.00
Dims: 0.16x0.14x0.16" (3.96x3.66x4.01mm)
Wt: 0.75ct (0.15g)
Tschikapa, Kasai Province, Congo
This cube of diamond is a single crystal, and its form is only moderately distorted, being a little tapered towards one end, and one corner seems to be missing (which is unlikely, as it is very difficult to damage a diamond). The real oddity is that in the center of the smaller face are two pits, readily visible with a loupe, which look like crystals of something else had been overgrown by the diamond, and subsequently disolved away. This seems incredibly unlikely to me, but that is what it looks like.
no photo
dia-106 ($ 42.00)
Tschikapa, Kasai Province, Congo
DIAMOND specimen dia-107
$ 53.00
Dims: 0.16x0.18x0.18" (0.41x0.46x0.46cm)
Wt: 0.95ct (0.19g)
Tschikapa, Kasai Province, Congo
This is a good cube of diamond, its form is distorted by two points of a second intergrown cube protruding slightly through three of its faces. It is translucent and a light gray in color. It also has a good luster and the surface is smoother than many natural diamonds.
no photo
dia-107 ($ 53.00)
Tschikapa, Kasai Province, Congo
DIAMOND specimen dia-99
$ 110.00
Dims: 0.22x0.21x0.19" (5.66x5.30x4.88mm)
Wt: 1.80ct (0.36g)
Tschikapa, Kasai Province, Congo
This diamond cube is only slightly distorted, being ever so slightly rhombic, perhaps 10% flattened, and having a single small bump due to another diamond crystal intergrown with the cube. The color is nearly colorless, having only a hint of yellow, and the rough, multi-faceted surface hides any transparency - the diamond looks translucent. But when examined with a loupe and under a bright light, it appears that the crystal's interior may be largely transparent - not only do some sparkles pass through it, but a rainbow is visible at certain angles from light entering the far side of the crystal (I only see this with my loupe).
no photo
dia-99 ($110.00)
Tschikapa, Kasai Province, Congo

 

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