آکانتیت
Sign in to saveAcanthite is a form of silver sulfide with the chemical formula Ag2S. It crystallizes in the monoclinic system and is the stable form of silver sulfide below . Argentite is the stable form above that temperature. As argentite cools below that temperature its cubic form is distorted to the monoclinic form of acanthite. Below 173 °C acanthite forms directly. Acanthite is the only stable form in normal air temperature.
Key facts
- Mineral.name
- Acanthite
- Mineral.category
- Sulfide mineral
- Mineral.image
- Acanthite - Imiter mine, Jbel Saghro, Tinghir, Drâa-Tafilalet, Morocco.jpg
- Mineral.imagesize
- 280px
- Mineral.caption
- Crystallized acanthite (4.0 × 2.5 × 1.5 cm) from Imiter mine, Jbel Saghro mountain range, Morocco
- Mineral.formula
- Ag2S
- Mineral.IMAsymbol
- Aca
- Mineral.strunz
- 2.BA.30a
- Mineral.system
- Monoclinic
- Mineral.class
- Prismatic (2/m) (same H-M symbol)
- Mineral.symmetry
- P21/n
- Mineral.unit cell
- a = 4.229 Å, b = 6.931 Å c = 7.862 Å; β = 99.61°; Z = 4
- Mineral.color
- Iron-black
- Mineral.habit
- Primary crystals rare, prismatic to long prismatic, elongated along [001], may be tubular; massive. Commonly paramorphic after the cubic high-temperature phase ("argentite"), of original cubic or octahedral habit
- Mineral.twinning
- Polysynthetic on {111}, may be very complex due to inversion; contact on {101}
- Mineral.cleavage
- Indistinct
- Mineral.fracture
- Uneven
- Mineral.tenacity
- Sectile
via Wikipedia infobox