Epidote Group Visible Spectra (350 - 1000 nm)

The common members of the epidote group minerals consist of allanite, clinozoisite, epidote, piemontite. The color of clinozoisite and epidote is due to their Fe³⁺ content and commonly varies from amber to brown. Piemontite contains Mn³⁺ and is red. Allanite is colored by iron and radiation damage and possibly by rare earth elements. 

• Images of representative epidote group spectra

• GRR 1282 amber clinozoisite spectrum; 1.10 mm thick sample from Gilgit, Pakistan. Data Files: perpendicular to c; parallel to c;

• GRR 1282 epidote spectrum; 1.104 mm thick sample from Gilgit, Pakistan. This is a different zone in the clinozoisite crystal portrayed above. Data Files: alpha; gamma;
• RDS 72 epidote spectrum; 1.0 mm thick olive-green crystal also from Pakistan with 8.84 wt% Fe₂O₃, described in Shannon & Rossman (1992) Phys Chem Min.
• GRR 438 epidote spectrum; 1.0 mm thick sample from an unspecified locality.
• GRR 1950 epidote spectrum; 1.121 mm thick sample from northwestern Kenya. Yellowish-brown British Museum sample 1973,589.

• GRR 2293 piemontite spectrum; 0.068 mm thick dark red sample from Whitewater River, near Palm Springs, California. alpha; gamma;
• GRR 2834 piemontite spectrum: 0.164 mm thick, red sample from Sidewinder Mountain, San Bernardino County, California. Data files: beta plus some alpha;  gamma
  

Link to references about the spectra of the epidote group

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