THE MINERAL CALAVERITE
- Chemistry: AuTe2, Gold Telluride.
- Class: Sulfides
- Subclass: Tellurides
- Uses: A very minor ore of gold and tellurium and as mineral specimens.
Specimens
For some reason gold has an affinity for the element tellurium, which is sometimes found naturally as
native tellurium.
Tellurium is a semi-metallic element which means that it has some properties of metals but not all or as strongly.
This helps provide an explanation for gold's, and other metals such as silver's, attraction to tellurium.
Other gold tellurides include sylvanite, (Silver Gold Telluride);
Crystals of calaverite are unique and of interest to collectors. Typically found as striated prisms that can be twinned causing sharp bends, reticulated individuals and skeletal or arborescent formations. These clusters remind many collectors of writing.
PHYSICAL CHARACTERISTICS:
- Color is silver white to brassy yellow.
- Luster is a bright metallic.
- Transparency: Crystals are opaque.
- Crystal System: Monoclinic; 2/m
- Crystal Habits include prismatic to more rarely tabular crystals that are often twinned into sharp bends, reticulated individuals and skeletal or arborescent formations. These are sometimes described as looking like writing. Also found as granular masses.
- Cleavage is absent.
- Fracture is conchoidal.
- Hardness is 2.5 - 3
- Specific Gravity is approximately 9.1 - 9.3 (very heavy even for metallic minerals).
- Streak is a yellow gray.
- Other Characteristics: Crystals tend to be deeply striated parallel to the prominent length.
- Associated Minerals include gold, quartz,
celestite,
fluorite,
pyrite, nagyagite, sylvanite,
krennerite and other rare telluride minerals. - Notable Occurrences include Cripple Creek in Teller County, Colorado and Calaveras County (from where it gets its name), California, USA; Nagyag, Romania; Kirkland lake Gold District, Ontario and Rouyn District, Quebec, Canada and Kalgoorlie, Australia.
- Best Field Indicators are crystal habit, density, softness, color, luster, association with other tellurides and gold and lack of cleavage.
 Amethyst Galleries' Mineral Gallery MINERALS |
CALAVERITE specimen caa-1
$ 80.00
$ 80.00
Dims: 1.7 x 1.2 x 0.3" (4.3 x 3.0 x 0.8 cm)
Wt: 10.5 g
Coin Mine, Cripple Creek, Colorado, U.S.A.
This thumbnail specimen consists of a host rock in which are embedded scores of tiny Calaverite crystals. Many of these crystals are incomplete due to damage during mining, but there are several clean, intact faces visible on the broader surfaces of the host rock, and one complete crystal is plainly visible when its thinnest edge is studied closely. The Calaverite crystals do not exceed 0.2" (5 mm), and the one complete crystal shows excellent monoclinic tabular form, with sharp edges and clean faces. All have a bright, silvery-white color and a bright metallic luster. The host rock is made up of simple, massive quartz that could use a small amount of cleaning with water and maybe a little bit of vinegar or another weak acid.
caa-1 ($ 80.00)
Coin Mine, Cripple Creek, Colorado, U.S.A.
CALAVERITE specimen caa-2
$ 100.00
$ 100.00
Dims: 1.7 x 1.1 x 0.5" (4.3 x 2.8 x 1.3 cm)
Wt: 20.9 g
Ajax Mine, Cripple Creek, Colorado, U.S.A.
A few dozen incomplete Calaverite crystals are embedded in the quartz host rock of this small specimen. None of these crystals appear to be complete, as they were broken during the specimen's mining. The crystals are large, however, and several show intact, striated faces. All have a bright, silvery-white coloration and a bright metallic luster. It would appear that a reniform crust of quartz coated the Calaverite crystals after they had formed on the quartz base. The quartz itself is white to gray in coloration and shows a substantial amount of rust-staining.
caa-2 ($100.00)
Ajax Mine, Cripple Creek, Colorado, U.S.A.
CALAVERITE specimen caa-3$ 380.00
Dims: 2.5 x 1.4 x 0.5" (6.4 x 3.6 x 1.3 cm)
Wt: 1.6 oz. (44.0 g)
Molly Kathleen Mine, Cripple Creek, Colorado, U.S.A.
If I had the funds, I would buy this piece in a second! It consists of layers of quartz matrix rock that are divided by many thin, broad veins of Calaverite. The Calaverite shows some definite crystal tendencies, but the veins apparently did not have enough room to form actual crystals. There are, however, noticeable striations on the exposed veins and the quartz host where parts of the veins flaked off. The Calaverite has a silvery-white coloration and a bright metallic luster. Interestingly, the quartz matrix is transparent and clear enough so that in certain areas, one can see veins of Calaverite that are still trapped inside of it! Maybe that is the aspect of this piece that I like so much.
caa-3 ($380.00)Molly Kathleen Mine, Cripple Creek, Colorado, U.S.A.
CALAVERITE specimen caa-4
$ 80.00
$ 80.00
Dims: 1.6 x 1.4 x 1.1" (4.1 x 3.6 x 2.8 cm)
Wt: 1.3 oz. (36.7 g)
Coin Mine, Cripple Creek, Colorado, U.S.A.
This thumbnail specimen consists of scores of tiny tabular Calaverite crystals that concentrate around and inside of hollows in the feldspar host rock. These crystals do not exceed 0.1" (3 mm) in any dimension, and most are broken or incomplete. Where intact, their monoclinic form is good, with sharp edges and striated but clean faces that possess a bright metallic luster. Their color is a bright silvery white, and the material is easily visible against the often dark-brown patches on which they rest. Most of the host rock, however, has a pink-orange or pale gray coloration and a pearly luster.
caa-4 ($ 80.00)
Coin Mine, Cripple Creek, Colorado, U.S.A.
CALAVERITE specimen caa-5
$ 180.00
$ 180.00
Dims: 1.9 x 1.7 x 1.3" (4.8 x 4.3 x 3.4 cm)
Wt: 2.8 oz. (79 g)
Cripple Creek, Colorado, U.S.A.
Scores of exposed, incomplete Calaverite blades are embedded in the siliceous base of this hand specimen. All that are exposed appear to be either damaged or broken and incomplete. They do not tend to exceed 0.2" (5 mm) in length or 0.1" (3 cm) in width, and are thinner than 1 mm. Where intact, they appear to have a good monoclinic form, and show the pale silvery-gray color and bright metallic luster of their specie. They are embedded in a white quartz vein that extends through a gray quartzite matrix- a few tiny orthorhombic krennerite (gold/silver telluride) crystals may also be present.
caa-5 ($180.00)
Cripple Creek, Colorado, U.S.A.
CALAVERITE specimen caa-6
$ 84.00
$ 84.00
Dims: 1.3 x 1.2 x 0.8" (3.4 x 3.0 x 2.1 cm)
Wt: 21 g
Cresson Mine, Cripple Creek, Colorado, U.S.A.
The gray and white matrix of this thumbnail specmien contains a few partial crystals and several veins of crystalline Calaverite. The few visible crystals that are present are broken and incomplete, but show some definable monoclinic, bladed form. All of the material has the standard bright, silvery-gray color and bright metallic luster. There is a considerable amount of Calaverite present in the matrix rock, which shows some rust-staining on one surface.
caa-6 ($ 84.00)
Cresson Mine, Cripple Creek, Colorado, U.S.A.
CALAVERITE specimen caa-7
$ 115.00
$ 115.00
Dims: 2.6 x 1.3 x 0.8" (6.7 x 3.3 x 2.2 cm)
Wt: 1.2 oz. (34 g)
Cripple Creek, Colorado, U.S.A.
This small cabinet specimen consists of a single large and many tiny Calaverite crystals that rest on a quartzite base. None of these Calaverites appear to be complete upon first glance, but many of the tiny ones are. The large one has dimensions of 0.3 x 0.1 x 0.1" (7 x 4 x 2 mm) and is broken and incomplete. However, it still shows vestiges of its monoclinic bladed form, and like all, has the bright silvery-white color and metallic luster of the specie. They are accompanied by and often intermixed with many small, milky quartz crystals that also rest on the base.
caa-7 ($115.00)
Cripple Creek, Colorado, U.S.A.