Idrialite
Idrialite is a rare hydrocarbon mineral with approximate chemical formula C22H14.
| Idrialite | |
|---|---|
Idrialite, Skaggs Springs Mine, Sonoma County, California (size: 6.3 x 4.1 x 1.8 cm | |
| General | |
| Category | Organic mineral |
| Formula (repeating unit) | C22H14 |
| IMA symbol | Id |
| Strunz classification | 10.BA.20 |
| Dana classification | 50.03.08.01 |
| Crystal system | Orthorhombic Unknown space group |
| Unit cell | a = 8.07, b = 6.42 c = 27.75 [Å]; Z = 4 |
| Identification | |
| Color | Greenish yellow, light brown, colorless |
| Cleavage | {001}, perfect; {100}, poor |
| Fracture | Conchoidal |
| Mohs scale hardness | 1.5 |
| Luster | Vitreous to adamantine |
| Specific gravity | 1.236 |
| Optical properties | Biaxial (+) |
| Refractive index | nα= 1.557 nβ = 1.734 nγ = 2.07 |
| Pleochroism | X = pale yellow; Y = Z = yellow |
| 2V angle | 84° |
| Ultraviolet fluorescence | Short UV=blue, orange, yellow, green white |
| References | |
Idrialite usually occurs as soft orthorhombic crystals, is usually greenish yellow to light brown in color with bluish fluorescence. It is named after Idrija, town in Slovenia, where its occurrence was first described.
The mineral has also been called idrialine, and branderz in German It has also been called inflammable cinnabar due to its combustibility and association with cinnabar ores in the source locality. A mineral found in the Skaggs Springs location of California was described in 1925 and named curtisite, but was eventually found to consist of the same compounds as idrialite, in somewhat different amounts. Thus curtisite is now considered to be merely a variety of idrialite.