THE MINERAL SCHORL
- Chemistry: NaFe3(Al,Fe)6Si6O18(BO3)3(OH)4, Sodium Iron Aluminum Boro-silicate Hydroxide.
- Class: Silicates
- Subclass: Cyclosilicates
- Group: Tourmalines
- Uses: mineral collection specimens, electrical uses and as ornamental stone.
Specimens
Schorl can form some very nice classic tourmaline crystals. Tourmaline crystals are interesting because they are hemimorphic, having a different shaped top from the bottom of the crystal. Some crystals of Schorl can reach a rather large size and can display a great variety of crystal faces.
Schorl can be a major component of igneous and metamorphic rocks. Although it is not the only black mineral common to such rocks, it is the only one that will form crystals with a clear triangular cross-section.
Long thin crystals of schorl are common as inclusions in quartz, forming the ornamental stone called "Tourmalinated Quartz". This stone is unique with its long needle to straw sized, arrow straight, prismatic crystals of pitch black schorl criss-crossing the clear colorless quartz. This attractive stone is used in semi-precious jewelry, carved figurines, obelisks, crystal balls, eggs and as a popular tumbled stone.
PHYSICAL CHARACTERISTICS:
- Color is black.
- Luster is vitreous to submetallic.
- Transparency: crystals are opaque.
- Crystal System is trigonal; 3 m.
- Crystal Habit is typically elongated three sided prisms. The terminations can be either a simple to complex trigonal pyramid or flat basal face. The prism faces are usually striated lengthwise. In cross section, all tourmalines will appear predominantly triangular in shape. Doubly terminated crystals are hemimorphic meaning that the two ends of the crystal are not exactly alike. Massive forms can also be found.
- Cleavage is absent although there is basal parting.
- Fracture is uneven to conchoidal.
- Hardness is 7 - 7.5
- Specific Gravity is 3.2+ (slightly heavier than average)
- Streak is white.
- Other Characteristics: Piezoelectric.
- Associated Minerals include those minerals associated with granitic pegmatites and metamorphic rocks such as micas, feldspars and quartz.
- Notable Occurrences include Brazil; Colorado; Appalachian mountains; Germany; Cornwall, England and many others.
- Best Field Indicators are crystal habit, overall triangular cross-section, striations, color and hardness.
 Amethyst Galleries' Mineral Gallery MINERALS |
SCHORL specimen scl-1
$ 45.00
$ 45.00
Dims: 2-5/8" x 2-1/4" x 3/4"
Wt: 2.7 oz
Pakistan
This specimen of Schorl Tourmaline is an accurate portrayal of the mineral's apperance: slender black crystals (these reach up to 2 inches long). However, the matrix that they are embedded in is odd. It seems to be made of a mass of fine platelets of either Fuchsite or green Muscovite. It really lends to the Schorl's appearance.
scl-1 ($ 45.00)
Pakistan
SCHORL specimen scl-2
$ 29.50
$ 29.50
Dims: 3" x 2" x 1-3/4"
Wt: 9.3 oz
Minas Gerais, Brazil
I like this piece of Schorl best of all because of its many crystal faces. Interestingly enough, it reminds me of elestial quartz in the way that it has so many crystal faces, as if it's composed of a tight cluster of crystals that stacked themselves on each other. The other unusual trait that this piece possesses is the fact that none of the prism faces have striations running the length of the crystal! I don't think I've ever seen tourmaline like that before...
scl-2 ($ 29.50)
Minas Gerais, Brazil
SCHORL specimen scl-3$ 150.00
Dims: 3.9" x 1.6" x 1.6" (9.9 x 4.1 x 4.1 cm)
Wt: 8.49 oz. (240.7 g)
Minas Gerais, Brazil
One of the more beautiful Schorl specimens that I have seen, this piece consists of a single crystal. It has a rough trigonal cross-section, and is in the form of a tapered prism with almost stalactitic formations hugging its sides! It does not have any flat crystal faces or angles, and the formations have a satiny luster. It would appear that each of these formations is made up of hundreds of tiny needle-like crystals that grow outwards at an almost parallel angle to the main prism. There seem to be a few patches of crushed needles on the prism, but the only spot that could be construed as definite breakage is on a small basal face at the tip of the crystal. Even so, it does not strike me as being human-induced damage. The crystal has the obligatory black color of Schorl and is, of course, opaque. It can be stood up on its base, and is one of the most beautiful Schorl specimens that I have seen. It is a personal favorite of Steve's.
scl-3 ($150.00)Minas Gerais, Brazil
SCHORL specimen scl-4$1500.00
Dims: 3.7" x 3.3" x 2.4" (9.4 x 8.4 x 6.1 cm)
Wt: 5.70 oz. (161.8 g)
Padre Paraiso, Minas Gerais, Brazil
This superb collector's piece consists of two clusters of rather tightly-grouped, needlelike Schorl crystals whose compact state makes me think of the term "parallel association". The larger of these clusters has dimensions of 3.6 x 1.3 x 0.9" (9.1 x 3.3 x 2.3 cm) and the smaller is about 2" (5 cm) shorter, but its other dimensions are similar, if a bit smaller. Both clusters are in excellent condition, showing no visible damage, and have very good form, though their compactness causes much intergrowth. They have the standard black color and opacity of Schorl, and their luster is bright and vitreous. Each cluster's outer crystals have grown and developed more than the inner crystals, so that both clusters are partially hollow and have an almost funnel-like appearance. Their bases are about 0.5" (1.3 cm) from each other, and the clusters grow away from each other at a 35- to 45-degree angle. They are held together by 2 hexagonal prismatic quartz crystals that are intergrown with crusts of muscovite, 2 of which partially coat each cluster. The quartz crystals both have a slightly dulled, pearly-to-vitreous luster and are translucent and somewhat milky. One is much flatter than the other, and seems to have an almost bladed form. The muscovite crystals are to small to determine without magnification, and may actually cover other Schorl or quartz crystals that hold the two clusters together. It is a magnificent specimen that can be displayed in a variety of positions.
scl-4 ($1500.00)Padre Paraiso, Minas Gerais, Brazil
SCHORL specimen scl-5
$ 60.00
$ 60.00
Dims: 1.8" x 1.6" x 1.2" (4.6 x 4.1 x 3.0 cm)
Wt: 3.20 oz. (90.8 g)
Minas Gerais, Brazil
This small hand specimen consists of what I call a "parallel association", of Schorl crystals, wherein more than one crystal has grown together in such a way that the cluster could be classified as a single crystal. This particular association is made up of at least 3 different crystals which are intergrown and have grown parallel to each other. Their trigonal prismatic form is somewhat warped due to their intergrowth, but is still discernable. One its more interesting aspects is the specimen's single, trigonal domed termination, which is integral and continuous, and acts as the termination for all of the crystals. The specimen has a black color and a vitreous luster, and is opaque. There are a few small spots of damage, including a conchoidal depression at the termination's tip. There are also a few "books" of muscovite growing off of its prism length. They have the standard crystal form, color, and luster of muscovite, and also show a small amount of damage.
scl-5 ($ 60.00)
Minas Gerais, Brazil
SCHORL specimen scl-6
$ 65.00
$ 65.00
Dims: 5.4 x 4.3 x 2.4" (13.7 x 10.9 x 6.1 cm)
Wt: 2 lbs., 0.5 oz. (923 g)
Minas Gerais, Brazil
Though I am not sure, I believe that this specimen came from the Sao Jose do Safira locality in Minas Gerais. It consists of a thick layer of intergrown Schorl and elbaite crystals that coat a base of albite. These crystals do not exceed 1.7" (4.3 cm) in length, and are in fair condition, as many of them are broken and incomplete. All have good trigonal prismatic forms, with rounded triangular cross-sections. Their edges are well-defined and their faces are striated and clean, possessing a pearly-to-vitreous luster. All have a generally black coloration, though some of the thinner crystals are brown or a dark olive-green. Actually, I really do not know if they are all Schorls or if there are elbaites among them, but I am going according to the fact that while most are completely opaque, some of the crystals are translucent or even dimly transparent. There is a single, flat tabular crystal resting among the Schorls that I am pretty sure is made of quartz, as it formed after the tourmaline and is somewhat translucent and clear. It does resemble the albite base, though, which is of the pseudohexagonal tabular variety known as cleavlandite. The cleavlandite, however, contains many geometrically aligned internal fractures, whereas none are visible in the crystal on top.
scl-6 ($ 65.00)
Minas Gerais, Brazil
SCHORL specimen scl-7
$ 35.00
$ 35.00
Dims: 3.5 x 2.3 x 1.6" (8.9 x 5.8 x 4.1 cm)
Wt: 5.45 oz. (154.5 g)
Sonora, Mexico
Several sprays of radiating Schorl crystals rest on the Schorl-and-quartz host rock of this hand specimen. These sprays are generally in very good condition, though all show scuff marks at their termination tips, and one appears to be broken and mostly incomplete. They range in length from 0.5 - 1.1" (1.3 - 2.8 cm), though there are many smaller crystals and sprays embedded in the host rock. All have a moderately good trigonal prismatic form, as most of their edges and faces are rounded. However, this is an aspect that commonly occurrs in this mineral- the crystals take on an almost plumose appearance, and all have a correspondingly silky luster. They have the obligatory black color and are opaque. The quartz that partly makes up the base rock consists of countless partly intergrown crystals, many of which are partially coated with a dull, white crust.
scl-7 ($ 35.00)
Sonora, Mexico
SCHORL specimen scl-8
$ 26.00
$ 26.00
Dims: 3.0 x 2.9 x 1.2" (7.6 x 7.4 x 3.0 cm)
Wt: 5.71 oz. (162.1 g)
Sonora, Mexico
Several Schorl crystals are scattered about the crystalline quartz host rock of this hand specimen. The crystals occur individually and in sprays and are generally in good condition, though there are several areas which show obvious breakage. The largest of these sprays consist of crystals that measure up to 1.1" (2.8 cm) in length. All have a rather indistinct form that borders on being plumose- no definite faces or edges are visible, and all have a silky luster. Their color is the standard black for the species, and every one of them is completely opaque. The crystals rest upon a bed of tiny hexagonal quartz crystals that are colorless and transparent, but are mostly covered by a dull, white crust. These quartzes extend from a base of what appears to be quartzite or granular, massive quartz. The underside of the specimen is quite interesting, as it is covered with a thick layer of more intergrown Schorl and quartz crystals.
scl-8 ($ 26.00)
Sonora, Mexico
SCHORL specimen scl-9
$ 35.00
$ 35.00
Dims: 3.1 x 3.0 x 2.0" (7.9 x 7.6 x 5.1 cm)
Wt: 6.69 oz. (189.9 g)
Sonora, Mexico
Several intergrown sprays of misshapen Schorl crystals rest on the quartz base rock of this specimen. The sprays are small, not exceeding 1.1" (2.8 cm) in length, and are in moderately good condition, as several of them show light to moderate damage. The crystals have an almost plumose form and are heavily intergrown with each other, so that their trigonal prismatic tendencies are essentially destroyed. This plumose habit gives the opaque, black crystals a beautiful, nearly silky luster. They are opaque, of course. The host rock on which they rest is made up almost entirely of small, tightly intergrown quartz crystals that are partly coated with a thin, dull white crust. Scattered among the quartz crystals are several much smaller, individual Schorl crystals that have similar tendencies as the sprays.
scl-9 ($ 35.00)
Sonora, Mexico
SCHORL specimen scl-10
$ 40.00
$ 40.00
Dims: 3.5 x 2.2 x 2.1" (8.9 x 5.6 x 5.3 cm)
Wt: 9.06 oz. (257.0 g)
Sonora, Mexico
At least 10 intergrown or individual sprays of radiating Schorl crystals are scattered on the mottled host rock of this hand specimen. These sprays range in size from 0.2 x 0.1 x 0.1" (5 x 3 x 3 mm) to 1.6 x 0.8 x 0.6" (4.1 x 2.0 x 1.5 cm) and are generally in good condition, as there is some minor damage present. Each spray is made up of several crystals that are both difficult to study and count due to their intense intergrowth. All appear to have a plumose formation, wherein their terminations are much larger than their bases. This effectively hides their trigonal prismatic form- one cannot even see a triangular shape in their cross-sections. Their color is black and their luster is rather dull and satiny, like velour. The host rock on which they rest is made up of countless tiny, intergrown quartz crystals, most of which are at least partly covered with a thin crust of a dull, white substance. There are many small sprays and individual Schorl crystals scattered among the quartz.
scl-10 ($ 40.00)
Sonora, Mexico
SCHORL specimen scl-11
$ 42.00
$ 42.00
Dims: 2.8 x 2.5 x 2.2" (7.1 x 6.4 x 5.6 cm)
Wt: 10.59 oz. (300.4 g)
Sonora, Mexico
This hand specimen is one of the few in our stock that contains mostly tabular Schorl crystals. These tabular crystals do not exceed 0.8" (2.0 cm) in diameter or 0.4" (1.0 cm) in thickness. Most of them are obviously damaged, and many are broken and incomplete. Where intact, their form is quite good, showing well-defined edges and clean faces that possess the standard vitreous luster. All have the classic black color and are opaque. The specimen is made up almost entirely of schorl- a few tiny patches of a rusty-white material are present, but they are too small to effectively define.
scl-11 ($ 42.00)
Sonora, Mexico
SCHORL specimen scl-12
$ 25.00
$ 25.00
Dims: 3.6 x 3.2 x 1.0" (9.1 x 8.1 x 2.5 cm)
Wt: 4.97 oz. (141.1 g)
Sonora, Mexico
Several individual crystals and clusters of Schorl rest on the quartz base of this hand specimen. These crystals reach lengths of about 0.8" (2.0 cm), and several of the most exposed are damaged and a few are broken. Like many other Schorl crystals from this locality, their trigonal prismatic form is evident, but not well defined. All have an almost plumose form, as the prism faces of each disseminate more and more towards the termination. They have the standard black color and a rather silky luster. The base on which they rest is made up of hundreds of small, intergrown quartz crystals that generally have excellent hexagonal prismatic form. Many are partly coated with a dull, white crust that I cannot define. There are also many smaller Schorl crystals trapped in this base.
scl-12 ($ 25.00)
Sonora, Mexico
SCHORL specimen scl-13
$ 25.00
$ 25.00
Dims: 3.7 x 3.2 x 1.0" (9.4 x 8.1 x 2.5 cm)
Wt: 4.98 oz. (141.1 g)
Sonora, Mexico
This hand specimen consists of hundreds of small, intergrown Schorl crystals. These crystals reach a maximum of 0.5" (1.3 cm) in diameter and 0.4" (1.0 cm) in thickness, and are in moderately good condition, as many spots of damage are evident. Their trigonal tabular form is quite good even with their intergrowth- all have reasonably well-defined edges and moderately clean faces that possess the standard vitreous luster. Their color is the obligatory black, and all are opaque. There is no host rock of any sort present.
scl-13 ($ 25.00)
Sonora, Mexico
SCHORL specimen scl-14
$ 28.00
$ 28.00
Dims: 3.6 x 2.5 x 2.1" (9.1 x 6.4 x 5.3 cm)
Wt: 12.3 oz. (347 g)
Sonora, Mexico
This Schorl specimen is a bit unusual in the fact that its trigonal form takes on an almost strictly fibrous habit. The specimen consists of intergrown clusters of compact, radiating needles that reach lengths of 1" (2.5 cm) or possibly more. They appear to be in good condition, though some obvious damage is visible. Their thinness and compact nature makes it difficult to study their trigonal form, but it appears to be good. This form lends an almost silky luster to the piece as a whole, and the Schorl has the classic black color and is opaque. There is a small amount of quartz present at the "base" of the piece, but no actual host rock is present.
scl-14 ($ 28.00)
Sonora, Mexico
SCHORL specimen scl-15
$ 35.00
$ 35.00
Dims: 3.6 x 2.9 x 1.6" (9.1 x 7.4 x 4.1 cm)
Wt: 8.68 oz. (246.3 g)
Sonora, Mexico
This hand specimen consists of many intergrown sprays of radiating schorl crystals that extend from a white quartz base. These sprays are generally in moderately good condition, as the most exposed surfaces of many sprays are worn or damaged. The crystals that make up the sprays are rather heavily intergrown with each other and achieve lengths of up to 1.4" (3.6 cm). All have an almost plumose, feathery form that gives the black crystals a somewhat silky luster. The base from which they extend is made up of countless tiny, intergrown quartz crystals mixed with a few smaller Schorls.
scl-15 ($ 35.00)
Sonora, Mexico
SCHORL specimen scl-16
$ 28.00
$ 28.00
Dims: 2.7 x 2.7 x 1.3" (6.9 x 6.9 x 3.3 cm)
Wt: 4.61 oz. (130.6 g)
Sonora, Mexico
This small hand specimen consists of several clusters of radiating Schorl crystals that rest on a whie quartz base. These clusters range in length from 0.2" (5 mm) or less up to 1.0" (2.5 cm), and most are at least slightly damaged. Their trigonal form is like that of many such specimens from this locality- the crystals have an almost plumose, feathery habit that shows no evidence of crystal edges or faces. This particular habit gives the black Schorls an almost silky luster. The largest of these clusters rest on top of the base, which is made up of countless tiny, intergrown quartz crystals, many of which are coated with a bright white coating that has a dull luster. Most of the smaller Schorl clusters and crystals, however, are interspersed throughout the host material.
scl-16 ($ 28.00)
Sonora, Mexico
SCHORL specimen scl-18
$ 35.00
$ 35.00
Dims: 3.2 x 1.9 x 1.9" (8.1 x 4.8 x 4.8 cm)
Wt: 10.2 oz .(289 g)
Minas Gerais, Brazil
A large chunk of a Schorl tourmaline crystal makes up this hand specimen. It shows considerable fresh damage, and just complete enough so that one can see its hexagonal outline when viewing along its prism length. A substantial part of its surface is intact, however, and shows the striations that are common on the prism lengths of most tourmalines. This particular Schorl crystal appears to have a thin coating of dark green elbaite, as one can easily see its color. Its core material, however, is black, opaque, and has a vitreous luster. There are a few bits of muscovite attached to it, but no host rock is present.
scl-18 ($ 35.00)
Minas Gerais, Brazil
SCHORL specimen scl-19
$ 35.00
$ 35.00
Dims: 3.8 x 2.8 x 2.4" (9.7 x 7.1 x 6.1 cm)
Wt: 10.28 oz. (291.3 g)
Sonora, Mexico
This small cabinet specimen consists of several clusters of radiaing Schorl prisms that grow off of an intergrown quartz/Schorl base. Each cluster is made up of several Schorl crystals that reach 1.1" (2.8 cm) in length. They are generally in good condition, though a few of the clusters show damage at their tops. The crystals have an indefinite form and an almost "fuzzy" appearance due to tiny, scale-like projections that cover them. All are black and opaque, and have a pearly luster.
scl-19 ($ 35.00)
Sonora, Mexico
SCHORL specimen scl-20$ 100.00
Dims: 3.2 x 2.7 x 1.6" (8.2 x 6.9 x 4.0 cm)
Wt: 4.4 oz. (125 g)
Pakistan
A rather odd and complex Schorl crystal extends through the sandblasted pegmatite matrix of this small cabinet specimen. It is in very good condition, showing very little fresh damage, and has dimensions of 2.8 x 1.1 x 0.8" (7.1 x 2.8 x 2.1 cm). Its trigonal form is rather warped and very odd- the crystal appears to have been broken and healed several times in several places, creating many disseminated projections and a very inconsistent termination. It has the standard black color and vitreous luster, and is, of course, opaque. Several tiny, transparent crystals are scattered about its surface- I am almost positive that they are colorless, transparent topazes, judging from their crystal form.
scl-20 ($100.00)Pakistan
SCHORL specimen scl-21
$ 40.00
$ 40.00
Dims:3.6x2.7x1.5" (9.1x6.9x3.8 cm)
Wt: 6.7oz. (189g)
Sonora, Mexico
This is a very thick crust of schorl crystals on a tiny amount of matrix. These schorl crystals do not photograph very well, but they have the luster of crushed black velvet, and are quite attractive. The individual crystals reach to nearly 1.0" (2.5cm) in length. The only damage visible on this specimen is to the edges, where it was pried from the host material.
scl-21 ($ 40.00)
Sonora, Mexico
SCHORL specimen scl-22
$ 27.00
$ 27.00
Dims:2.5x2.3x1.5" (6.4x5.8x3.8 cm)
Wt: 6.2oz. (176g)
Pedra Alta Mine, Goiabeira, Minas Gerais, Brazil
This is an interesting specimen of schorl tourmaline with a small amount of albite and muscovite matrix. Due to the angles of the termination faces, I believe this to be a single crystal with multiple terminations at one end. This growth pattern is rather unusual, and quite attractive. This is a very shiny, reflective crystal, and it looks MUCH better in person than in the photograph. There is moderate damage to one side and the back of this specimen; the display face, however, is undamaged.
scl-22 ($ 27.00)
Pedra Alta Mine, Goiabeira, Minas Gerais, Brazil
SCHORL specimen scl-23
$ 25.00
$ 25.00
Dims: 3.0x1.0x0.8" (7.7x2.5x2.3 cm)
Wt: 1.06 oz. (29.9g)
Sceptre Claims, Emerald Lake, Yukon, Canada
This schorl tourmaline specimen is mostly a solid array of fine crystals radiating from a point. Accompanying the schorl is a crust of tiny translucent quartz crystals intergrown with more tiny schorls and some black mica blades. There is a second smaller schorl crystal/assemblage near one end and nearly at right angles to the primary one.
scl-23 ($ 25.00)
Sceptre Claims, Emerald Lake, Yukon, Canada