Andradite and Epidote
| ID | 443 | |
|---|---|---|
| Mineral |
Andradite
Epidote |
|
| Location | Kayes Region - Mali | |
| Fluorescence | LW-UV: close SW-UV: close |
|
| Mindat.org |
View Andradite information at mindat.org View Epidote information at mindat.org |
|
Mindat data
| ID | 223 |
|---|---|
| Long ID | 1:1:223:5 |
| Formula |
Ca3Fe3+2(SiO4)3
|
| IMA Status |
0 1 |
| General Appearance | A yellowish-grey to dark straw-yellowish, vitrous mineral with an uneven fracture (From the description of d'Andrada 1800). |
| Occurrence | Contact metamorphosed impure limestone |
| Other Occurrences | In skarns from contact metamorphosed impure limestones or calcic igneous rocks; in chlorite schists and serpentinites; in alkalic igneous rocks, then typically titaniferous. |
| Discovery Year | 1800 |
| Diapheny | Transparent,Translucent |
| Tenacity | brittle |
| Colour | Yellow, greenish yellow to emerald-green, dark green; brown, brownish red, brownish yellow; grayish black, black; may be sectored |
| Hardness (min) | 6.5 |
| Hardness (max) | 7.0 |
| Lustre | Vitreous, Resinous |
| About the name |
Named in 1868 by James Dwight Dana in honor of José Bonifácio de Andrada e Silva [June 13, 1763 Santos, Brazil - April 6, 1838 Niterói, Brazil], Brazilian mineralogist, who first described and named what Dana (1868) defined as a subvariety of andradite. d'Andrada had earlier, in 1800, discovered a yellowish-grey mineral from a mine (Wirum?) near |
| Streak | White |
| Crystal System | Isometric |
| Fracture type | Irregular/Uneven,Conchoidal |
| Morphology | Commonly well-crystallized dodecahedra, trapezohedra, or combinations, to 5 cm. Also granular to massive. |
| shortcode_ima | Adr |
| Group | Garnet Group |
| ID | 1389 |
|---|---|
| Long ID | 1:1:1389:1 |
| Formula |
Ca2(Al2Fe3+)[Si2O7][SiO4]O(OH)
|
| IMA Status |
0 1 |
| Other Occurrences | Regional and contact metamorphic rocks. Saussuritisation (alteration of plagioclase). |
| Discovery Year | 1801 |
| Diapheny | Transparent,Translucent,Opaque |
| Cleavage | Perfect on {001}, imperfect on {100} |
| Tenacity | brittle |
| Colour | Yellowish-green, green, brownish-green, black |
| Hardness (min) | 6.0 |
| Hardness (max) | 6.0 |
| Lustre | Vitreous |
| About the name | Named in 1801 by Rene Just Haüy from the Greek επιδοσιζ ("epidosis"), meaning "increase", in allusion to the crystal characteristic of one longer side at the base of the prism. |
| Streak | Colourless |
| Crystal System | Monoclinic |
| Cleavage Type | Perfect |
| Fracture type | Irregular/Uneven |
| Morphology | Crystals prismatic to 35 cm, also stubby, rarely tabular or pseudo-octahedral. Fibrous, coarse to finely granular, massive. Prismatic crystals may show a pseudo-hexagonal cross-section. |
| Twinning | On {100}, contact, lamellar, common. |
| shortcode_ima | Ep |
| Group | Epidote Group |
Details
Price: € 15
Dimensions: Not registered
Weight: Not registered
Visibile in overview:
Notes:
| Symbol | Element | |
|---|---|---|
| Al | Aluminium | |
| Ca | Calcium | |
| Fe | Iron | |
| H | Hydrogen | |
| O | Oxygen | |
| Si | Silicium |