Epidote
Epidote is a silicate mineral prized by collectors for its exceptional color range, with several world-class Chinese localities.
About Epidote
Epidote is classified as a silicate mineral in the epidote group and has the chemical formula {Ca2}{Al2Fe3+}[Si2O7][SiO4]O(OH). It crystallizes in the monoclinic system and is one of the most visually varied minerals in the collector market. Its combination of structural character and global distribution make it a recognized species in both systematic and aesthetic collections.
Identification & care
Specimens usually show prismatic striated crystals, often tabular; also massive, granular, fibrous; radiated groups. Its color range is broad, including characteristic pistachio green ('pistachite'), yellowish green, olive green, dark green to black, and rarely colorless. The luster is vitreous, resinous, the streak is colorless to grayish, and specimens are typically transparent, translucent. The cleavage is perfect on {001}, imperfect on {100}. The fracture is irregular/uneven, sub-conchoidal, which aids identification.
Collector context
How it forms
The geological setting for Epidote is typically common in metamorphic rocks (blueschist, greenschist, amphibolite facies); contact metamorphic zones; hydrothermal veins; alteration product of plagioclase (saussuritization). It is commonly found in association with quartz, chlorite, actinolite, hornblende, garnet, calcite, prehnite.
Classic Chinese localities
**Huanggang Fe-Sn deposit** is an important Chinese source for the species.
Why collectors care
Epidote is a frequently-sought species in serious collections because its habit is recognizable, its color often strong, and its best examples unmistakable even at a distance. Chinese material has driven much of the recent visual shift in the species — sharper crystals, deeper colors, cleaner matrix.
What affects value
Value in Epidote is assessed, in typical order of weight, against: (1) locality provenance; (2) size relative to the species norm; (3) crystal form and termination sharpness; (4) color saturation and zoning; (5) transparency and internal clarity; (6) matrix quality and aesthetic balance; (7) condition (absence of damage, chips, or repair). Cleaning quality and verified locality documentation act as multipliers across the above.
Naming history
The name Epidote has a specific etymological and historical context — see Mindat's reference entry for provenance details. We have retained naming data at the record level; published prose is paraphrased from factual fields rather than copied from source.