Argentojarosite
AgFe3+3(SO4)2(OH)6 [CNMNC approved formula]
Named in 1923 for the silver content and relationship to jarosite.
| IMA status : | Redefined IMA Approved; 2003 () |
| CLASSIFICATION | |
| Dana (8th edition) : |
30.02.05.05 |
| (30) Anhydrous Sulfates Containing Hydroxyl or Halogen | |
| (30.02) where (A B)2 XO4 Zq | |
| (30.02.05) Alunite Group (Jarosite Subgroup) | |
| Nickel-Strunz (10th edition) : |
07.BC.10 |
| (07) Sulfates (selenates, tellurates, chromates, molybdates, wolframates) | |
| (07.B) Sulfates (selenates, etc.) with Additional Anions, without H2O | |
| (07.BC) With medium-sized and large cations | |
| Crystal system: | Trigonal System |
| Point group (H-M): | 3m — ditrigonal-pyramidal |
| Unit cell: | a = 7.35 Ǻ, c = 16.58 Å |
| Crystal Habit: | Crystals microscopic; micaceous; flattened with hexagonal outline; fine-grained masses and coatings |
| Color: | Yellow to brown |
| Diaphaneity: | Transparent to translucent |
| Luster: | Brilliant |
| Hardness (Mohs): | 3.5 - 4.5 |
| Measured Density: | 3.62 to 3.66 g/cm3 |
| Cleavage: | 1; {0001} |
| Tenacity: | Brittle |
| Fracture: | Uneven to conchoidal |
| Streak: | Yellow |
| Geologic Setting: | An uncommon secondary mineral in the oxidized portions of silver- and sulfide-bearing mineral deposits. |
| Mineral Association: | Anglesite, barite, quartz (Tintic Standard mine, Utah, USA) |
Yellow crystalline massive argentojarosite.Origin: Eagle Mine, Juab County, Utah, USA.
Photo: Jeff Weissman