THE MINERAL MIARGYRITE

  • Chemistry: AgSbS2, Silver Antimony Sulfide
  • Class: Sulfides
  • Subclass: Sulfosalts
  • Uses: Mineral specimens and as a minor ore of silver.
  • Specimens

Miargyrite is a another interesting silver sulfide mineral that is popular with collectors who love to collect silver bearing minerals. Other silver sulfide minerals include stephanite, pyrargyrite, polybasite, proustite, argyrodite, andorite and acanthite among many others. It is easy to confuse miargyrite with some of these other minerals, but its crystal habit and unusual streak will generally suffice to differentiate it. Miargyrite is a sulfosalt, a segment of sulfides where the antimony acts more like a metal than a non-metal and occupies a position where it is bonded to sulfurs.

PHYSICAL CHARACTERISTICS:

  • Color is iron black to steel gray.
  • Luster is metallic.
  • Transparency: Crystals are opaque.
  • Crystal System: Monoclinic; 2/m.
  • Crystal Habits include complex crystals with a tabular character and massive.
  • Cleavage: Not discernible.
  • Fracture: Conchoidal.
  • Hardness is 2 - 2.5
  • Specific Gravity is 5.1 - 5.3 (somewhat heavier than average for metallic minerals)
  • Streak is cherry-red.
  • Other Characteristics: Specimens will darken with exposure to light.
  • Associated Minerals include pyrargyrite, polybasite, proustite, galena, chalcopyrite and acanthite.
  • Notable Occurrences include Saxony and the Harz Mountains of Germany; Pribram, Czech Republic; San Juan, Colorado; Silver City, Idaho; Cerbat Mountains, Arizona and California, USA; Romania; Chile and Bolivia.
  • Best Field Indicators are crystal habit, streak, softness, color and luster.
MIARGYRITE specimens:
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MIARGYRITE specimen mia-1
$ 72.00
Dims: 1.3 x 1.2 x 1.1" (3.2 x 3.0 x 2.7 cm)
Wt: 1.3 oz. (37 g)
Kelly Mine, Red Mountain, Randsburg Mining District, San Bernardino County, California, U.S.A.
Massive Miargyrite makes up the bulk of this small hand specimen. This sulfosalt shows no crystal form and has the dark silvery-gray color and metallic luster that is common in most silver-bearing sulfides. It probably occurred as veins in the brown and white quartz matrix that is present in the piece.
no photo
mia-1 ($ 72.00)
Kelly Mine, Red Mountain, Randsburg Mining District, San Bernardino County, California, U.S.A.
MIARGYRITE specimen mia-2
$ 138.00
Dims: 1.1x0.7x0.6" (2.8x1.7x1.5 cm)
Wt: 0.46 oz. (13.1g)
San Genare, Huancavelica, Peru
This miargyrite thumbnail is a thick crust of tiny crystals on a base of another silver sulfide, with a tiny amount of other minerals present. The crystals of miargyrite are so tiny that they appear as a field of sparkles unless a high power loupe is used, which resolves them into silvery flattened crystals with good form - they are rounded and the faces have a slight convex curvature. The host mineral (about 50% by weight) is a vein of another silver sulfosalt, which I believe is polybasite. It has a superficially metallic appearance, and under a loupe it appears translucent and deep cherry red, with deep red reflections from internal fractures.
no photo
mia-2 ($138.00)
San Genare, Huancavelica, Peru
 

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