642 - Epidote

ID	642
Mineral	Epidote
Location	Iran
Fluorescence	LW-UV: close SW-UV: close
Mindat.org	View Epidote information at mindat.org

ID	1389
Long ID	1:1:1389:1
Formula	`Ca₂(Al₂Fe³⁺)[Si₂O₇][SiO₄]O(OH)`
IMA Status	APPROVED GRANDFATHERED
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 René Just Haüy from the Greek ἐπίδοσις (epidosis), referring to the crystal’s characteristic in which one side of its base is more extended than the other.
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

Epidote