546 - Epidote and Melanite

ID	546
Mineral	Epidote Melanite
Location	Vera Cruz - Mexico
Fluorescence	LW-UV: close SW-UV: close
Mindat.org	View Epidote information at mindat.org View Melanite information at mindat.org

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

ID	7443
Long ID	1:1:7443:4
IMA Status	0 1
Variety of	223
Entry type	2
Description	A black Ti-bearing (up to 11.5 mass% TiO2, usually ~5 or less mass%) variety of Andradite.
Colour	Black
Hardness (min)	6.5
Hardness (max)	7.0
Lustre	Vitreous, Resinous
About the name	Named in 1799 by Abraham Gottlob Werner from the Greek μελανός ("melanos") for "black".
Crystal System	Isometric

Epidote and Melanite