THE MINERAL PYRARGYRITE
- Chemistry: Ag3SbS3, Silver Antimony Sulfide
- Class: Sulfides
- Subclass: Sulfosalts
- Uses: an ore of silver and as mineral specimens.
Specimens
Pyrargyrite is isostructural with proustite, a silver arsenic sulfide. Isostructural means that the two minerals have the same structure but a different chemistry. There is some substitution of the antimony and arsenic. But in both minerals, the substitution is minor and no solid solution is believed to exist between the two minerals.
Pyrargyrite is the more common of the two minerals and is usually found in the same ore veins with proustite, silver and other silver sulfides. Its crystals can be striking and very attractive. However, as with other silver minerals, it is reactive to light and can darken upon exposure, and a translucent specimen can quickly become essentially opaque. Therefore, fine specimens should be stored in closed containers with exposure to light limited.
PHYSICAL CHARACTERISTICS:
- Color is a dark red to red-black.
- Luster is adamantine.
- Transparency crystals are translucent to nearly opaque.
- Crystal System trigonal; 3m
- Crystal Habits: include prismatic crystals with rhombohedral and scalenohedral faces forming terminations. There is no perpendicular mirror plane and therefore a hemimorphic crystal can be seen, in some rare examples, with differing terminations at the top and bottom of the crystal. Typical crystals are poorly formed and modified heavily by secondary faces. Also found massive.
- Cleavage is sometimes distinct in three directions forming rhombohedrons.
- Fracture is conchoidal.
- Hardness is 2.5
- Specific Gravity is approximately 5.8 (very heavy for translucent minerals)
- Streak is a dark cherry red.
- Associated Minerals include
proustite,
silver,
tetrahedrite,
calcite,
argentite . quartz, galena, sphalerite and other silver vein minerals. - Other Characteristics: darkens upon exposure to light and crystals are frequently striated.
- Notable Occurances include Atacama, Chile; silver mines in Saxony Germany and in Colorado, USA and Cobalt, Onatario, Canada.
- Best Field Indicators are crystal habit, density, association with silver sulfides and color.
 Amethyst Galleries' Mineral Gallery MINERALS |
PYRARGYRITE specimen pyg-1
$ 50.00
$ 50.00
Dims: 3/4" x 7/8" x 5/8"
Wt: 15.9 g. w/ specimen box
Veta Grande, Zacatecas, Mexico
At least a dozen tiny crystals infest this Mexican thumbnail specimen. They have a gray color, a dull metallic luster, and occasionally show a glint of deep red, which is common for this material. One crystal on the specimen achieves a length of over 1/4 inch in length, and all the others are smaller. Crystal form is definite, but classic shapes associated with the trigonal system are indeterminate. Actually, the crystals remind me most of those of many Peruvian bournonites that I've seen! The specimen has no host rock, but there seems to be a thin calcite crust that coats the crystals at their bases. It is affixed to a plastic specimen box with a hinged lid. It's an attractive little specimen!
pyg-1 ($ 50.00)
Veta Grande, Zacatecas, Mexico
PYRARGYRITE specimen pyg-2
$ 60.00
$ 60.00
Dims: 1-1/8" x 3/4" x 1/2"
Wt: 18.3 g. w/ specimen box
Veta Grande, Zacatecas, Mexico
There are 5 discernable crystals on this thumbnail specimen, on a matrix that seems to be composed of massive Pyrargyrite interspersed with veins of calcite. Of these 5 crystals, only one is nearly complete, with only a small amount of material missing from a spot near its base. It has a six-sided columnar crystal form with 3 primary and 3 secondary faces and a basal pinacoid termination that has a small oddity; at the center of the termination a tiny, shallow 3-sided pyramid is protruding. The crystals all have a gray color with a submetallic luster, and points of deep red reflected color are noticeable at certain angles. The specimen is affixed inside a plastic specimen box.
pyg-2 ($ 60.00)
Veta Grande, Zacatecas, Mexico
PYRARGYRITE specimen pyg-3
$ 37.00
$ 37.00
Dims: 0.9" x 0.6" x 0.6" (2.3 x 1.5 x 1.5 cm)
Wt: 10.3 g
Santo Nino vein, Fresnillo, Zacatecas, Mexico
There appear to be 4 or 5 intergrown Pyrargyrite crystals that make up this thumbnail specimen. Four of them are more than 70% complete, though their crystal form is somewhat warped due to their intergrowth and moderate damage. One crystal is broken and incomplete, and is not as completely intergrown as the others. Three of the crystals make up the bulk of the specimen's mass- they are all of nearly similar size, and the only way to easily discern them is by examining their terminations. Two smaller crystals can be seen along the prism lengths of these larger crystals; their form is nearly tabular in appearance, and their terminations are somewhat rounded. All have a dark gray color and metallic luster with hints of a deep red color that is quite visible in a bright light. If the light is bright enough, their opacity turns into a dim translucence. I have affixed the specimen inside a domed thimble box.
pyg-3 ($ 37.00)
Santo Nino vein, Fresnillo, Zacatecas, Mexico
PYRARGYRITE specimen pyg-4
$ 60.00
$ 60.00
Dims: 1.5" x 0.6" x 0.5" (3.8 x 1.5 x 1.3 cm)
Wt: 10.3 g
Santo Nino vein, Fresnillo, Zacatecas, Mexico
This large thumbnail specimen consists of several warped, intergrown Pyrargyrite crystals. They have forms that are rather difficult to determine due to damage and their intergrowth, and their moderate gray coloration and metallic luster look like those of a variety of related minerals. However, they have one trait that discerns them from all others. When one holds the specimen up to the light, the Pyrargyrite will glow with a deep red translucence. However, there is some material on the specimen that does not glow this color. It shows much better, more defined crystal form than the Pyrargyrite, and its gray color is a bit darker. Also, its luster is not quite as bright, and its crystals show lengthwise striations that I do not see on the Pyrargyrite specimens that I have available for examination. I believe that this material is a closely-related sulfide, possibly Argentite or Stephanite. Interestingly, it surrounds a Pyrargyrite crystal, the termination of which is the only visible portion. I have affixed it inside a domed plastic thimble box for display.
pyg-4 ($ 60.00)
Santo Nino vein, Fresnillo, Zacatecas, Mexico
PYRARGYRITE specimen pyg-5
$ 74.00
$ 74.00
Dims: 1.2" x 0.9" x 0.6" (3.0 x 2.3 x 1.5 cm)
Wt: 13.7 g
Santo Nino vein, Fresnillo, Zacatecas, Mexico
This thumbnail specimen is dominated by a large partial Pyrargyrite crystal that rests on a base of intergrown and incomplete Pyrargyrites, chalcopyrite, and possibly other metal sufides. Though it is not complete, its hexagonal cross-section is well-defined, and it has a partially-healed break that is covered with small, complex faces that are arranged in a hexagonal pattern. It has the dark gray coloration and metallic luster that one would expect from Pyrargyrite, and appears to be opaque until it is examined in bright light. Then, one can see that the material shows flashes of translucence and sometimes even transparence, and a beautiful deep red color. The other intergrown crystals in the specimem are not as large as the biggest one (it measures 0.5" in length and 0.4" in diameter, or 1.3 x 1.0 cm, respectively) and they have discernable crystal form but no definite shape. The piece is affixed inside a do
pyg-5 ($ 74.00)
Santo Nino vein, Fresnillo, Zacatecas, Mexico
PYRARGYRITE specimen pyg-9
$ 45.00
$ 45.00
Dims: 0.6 x 0.5 x 0.4" (1.5 x 1.2 x 1.1 cm)
Wt: 4 g
Zacatecas, Mexico
This small thumbnail piece consists of a cluster of many tiny Pyrargyrites. These crystals do not exceed 0.3 x 0.2 x 0.2" (8 x 5 x 4 mm) but are generally in very good condition, showing no fresh damage. Their hexagonal prismatic form is very good, and all show a dark gray color and bright, nearly metallic luster that is caused by an oxidation coating and is common for this mineral. This coating also renders them essentially opaque in normal light. There is a very small amount of a white host rock present.
pyg-9 ($ 45.00)
Zacatecas, Mexico
PYRARGYRITE specimen pyg-6
$ 30.00
$ 30.00
Dims: 1.2 x 1.0 x 0.6" (3.0 x 2.6 x 1.5 cm)
Wt: 0.3 oz. (9 g) w/ foam base
Veta Grande, Zacatecas, Mexico
At least 2 misshapen and likely incomplete Pyrargyrite crystals rest on the edge of the quartz base of this thumbnail piece. The crystals are in good condition, showing light fresh damage and considerable older, healed damage. The crystals do not exceed 0.2" (5 mm) in either length or diameter and show rather warped, incomplete hexagonal forms that are difficult to define. Both show the standard dark gray color and dull metallic luster, and are opaque in bright light. Several other Pyrargyrites rest on the underside of the piece- they are all misshapen and incomplete. The quartz base consists of a druse of many crystals, a few of which show slight sceptering. The piece is hot-glued into a plastic thumbnail box.
pyg-6 ($ 30.00)
Veta Grande, Zacatecas, Mexico
PYRARGYRITE specimen pyg-7
$ 33.00
$ 33.00
Dims: 0.7 x 0.7 x 0.4" (1.9 x 1.8 x 0.9 cm)
Wt: 0.5 oz. (13 g) w/ specimen box
Veta Grande, Zacatecas, Mexico
A few incomplete Pyrargyrite crystals rest on the gray base rock of this thumbnail piece. These crystals are in fair to good condition, showing moderate to considerable damage, and do not exceed 0.4" (1.0 cm) in either length or width. Where intact, they show reasonably good hexagonal form that is nearly bladed in habit. All have a dark gray color and a dull metallic luster, but show glimpses of dim transparence and deep red color when held up to the light. The piece is affixed inside a plastic thumbnail box.
pyg-7 ($ 33.00)
Veta Grande, Zacatecas, Mexico
PYRARGYRITE specimen pyg-10
$ 60.00
$ 60.00
Dims: 0.94x0.67x0.55" (2.4x1.7x1.4cm)
Wt: 0.39oz. (10.9g)
Proana Mine, Fresnillo, Zacatecas, Mexico
This thumbnail specimen is mostly a single large crystal of pyrargyrite, judging by the deep and perfectly parallel striations along the sides of the crystal. There are many terminations which, again, are parallel. There is a second, smaller crystal whose striations are at a slightly different angle. The specimen appears a metallic black, but close examination reveals the deep red color of the species, especially as bright red reflections from internal fractures. Under a loupe and a bright light, the red appears everywhere, as the translucency of the crystals is revealed. There is a small amount of milky quartz crystals, upon which this undamaged pyrargyrite was perched.
pyg-10 ($ 60.00)
Proana Mine, Fresnillo, Zacatecas, Mexico
PYRARGYRITE specimen pyg-11
$ 45.00
$ 45.00
Dims: 0.98x0.67x0.51" (2.5x1.7x1.3cm)
Wt: 41.0ct (8.20g)
Proana Mine, Fesnillo, Zacatecas, Mexico
This is almost a wonderful specimen of pyrargyrite. It shows nice crystalization, with a variety of shapes including parallel prismatic crystals, although there are a few similar appearing hexagonal polybasite crystals also present. The pyrargyrite is distinctive in that it is ever-so-slightly translucent and appears dimly red when viewed carefully. If the pyrargyrite had not darkened to nearly black, this would be a nice specimen, indeed.
pyg-11 ($ 45.00)
Proana Mine, Fesnillo, Zacatecas, Mexico
PYRARGYRITE specimen pyg-13
$ 60.00
$ 60.00
Dims: 1.16x0.78x0.68in (2.95x1.99x1.73cm)
Wt: 0.33oz (9/3g)
Proana Mine, Fresnillo, Zacatecas, Mexico
This specimen has several prismatic crystals of pyrargyrite, one of which is relatively large and nice. All are essentially black and opaque, however - I cannot detect any redness to the color.
pyg-13 ($ 60.00)
Proana Mine, Fresnillo, Zacatecas, Mexico
PYRARGYRITE specimen pyg-14
$ 45.00
$ 45.00
dims mm=31.2x28.7x20.2
wt g=19.9
Peregrina Mine, Guanajuato, Mexico
This specimen primarily consists of intergrown crystals of pyrargyrite. While they have recognizable hexagonal cross sections, there are no crystal terminations visible. Also, the pyrargyrite has darkened to an opaque silver black color with a vitreous luster, and no sign of transparency or red color.
pyg-14 ($ 45.00)
Peregrina Mine, Guanajuato, Mexico
PYRARGYRITE specimen pyg-15
$ 30.00
$ 30.00
dims mm=19.83x11.68x8.79
wt g=5.5
Peregrina Mine, Guanajuato, Mexico
This pyrargyrite specimen is essentially black and opaque - I cannot detect any red translucency or flashes. It does show some crystal form, although there are no terminations visible.
pyg-15 ($ 30.00)
Peregrina Mine, Guanajuato, Mexico
PYRARGYRITE specimen pyg-16
$ 48.00
$ 48.00
dims mm=37.59x24.74x22.28
wt g=31.1
Proana Mine, Fresnillo, Zacatecas, Mexico
This piece is mostly pyrargyrite, which unfortunately shows little crystal form except along the striated side of the crystal. Accompanying the pyrargyrite are hollow hexagons that look like a quartz druze coated something else since disappeared, and numerous small transparent calcite crystals.
pyg-16 ($ 48.00)
Proana Mine, Fresnillo, Zacatecas, Mexico