Phoenicochroite
| Phoenicochroite | |
|---|---|
Deep red Phoenicochroite cystal, with orange-yellow schwartzembergite. San Francisco Mine, , Chile. Photo width 1.5 mm.
|
|
| General | |
| Category | Chromate mineral |
|
Formula (repeating unit) |
Pb2O(CrO4) |
| Strunz classification | 7.FB.05 |
| Crystal system | Monoclinic |
| Crystal class | Prismatic (2/m) (same H-M symbol) |
| Space group | C2/m |
| Unit cell | a = 14 Å, b = 5.67 Å, c = 7.13 Å; β = 115.22°; Z = 4 |
| Identification | |
| Color | Dark red, bright red |
| Crystal habit | Tabular crystals; thin coatings, and massive |
| Cleavage | Perfect on {201} |
| Tenacity | Sectile |
| Mohs scale hardness | 2½ |
| Luster | Adamantine, resinous |
| Streak | Brick-red |
| Diaphaneity | Translucent |
| Specific gravity | 7.01 |
| Optical properties | Biaxial (+) |
| Refractive index | nα = 2.380, nβ = 2.440, nγ = 2.650 |
| Birefringence | 0.270 (δ) |
| 2V angle | 58° (measured) |
| References | |
Phoenicochroite, also known as melanochroite, is a lead chromate mineral with formula Pb2OCrO4. It forms striking orange red crystals. It was first discovered in 1839 in Beryozovskoye deposit, Urals, Russia. It is named from the Greek word φοίυικος for "deep red" and χρόα for "color," in allusion to its color.
...
Wikipedia