Colour

Various shades of red from a brownish to dark purplish red

Cause of colour

Iron - idiochromatic

Optical Character

Isotropic                   

Pleochroism

Not applicable

Colour change

No

Spectrum; no polar Calibration in nm.

617 weak; 576 & 527 moderate to strong and broad. 505 strong to very strong and broad merging with 527 when Fe. content is high. 462 weak to strong as Fe increases.

Ordinary ray

Not applicable

Extraordinary ray

Not applicable

Alpha ray

Not applicable

Beta ray

Not applicable

Gamma ray

Not applicable

Emission lines

No

Database reference

All above in RD5 See also RD1 and RD3 for other red garnets

Notes

RI rises with Fe. RD0323-1.760; RDF0039-1.770; RDF0121-1.784