Dollaseite-(Ce)
| Dollaseite-(Ce) | |
|---|---|
| General | |
| Category | Silicate mineral |
| Formula | CaCeMg2AlSi3O11F(OH) |
| IMA symbol | Dls-Ce |
| Crystal system | Monoclinic |
| Crystal class | Prismatic (2/m) (same H-M symbol) |
| Space group | P21/m |
| Identification | |
| Formula mass | 551.04 g/mol |
| Color | Brown |
| Crystal habit | Massive, somewhat prismatic, equant when subhedral |
| Twinning | On [100] |
| Cleavage | Indistinct, epidote has one good cleavage on one side |
| Fracture | Flat regular to uneven |
| Mohs scale hardness | 6.5–7 |
| Luster | Vitreous |
| Streak | light brown |
| Diaphaneity | Translucent |
| Specific gravity | 3.9 |
| Optical properties | Biaxial (+) |
| Refractive index | nα = 1.715 nβ = 1.718 nγ = 1.733 |
| Birefringence | δ = 0.018 |
| Pleochroism | Strong |
| References | |
Dollaseite-(Ce) is a sorosilicate end-member epidote rare-earth mineral which was discovered by Per Geijer (1927) in the Ostanmossa mine (Östanmossa gruva), Norberg district, Sweden. Dollaseite-(Ce), although not very well known, is part of a broad epidote group of minerals which are primarily silicates, the most abundant type of minerals on earth. Dollaseite-(Ce) forms as dark-brown subhedral crystals primarily in Swedish mines. With the ideal chemical formula, CaREE3+
Mg
2AlSi
3O
11,(OH)F, dollaseite-(Ce) can be partially identified by its content of the rare earth element cerium.