Diaspore Visible Spectra (400 - 1100 nm)

Diaspore, AlO(OH), would normally be colorless if chemically pure.  Traces of metal ions (Mn, Fe, Cr) cause color in this mineral.

Image of the diaspore absorption spectrum

• RDS 62047-42 spectrum, 6K; from Muğla Province, Turkey, 10.00 mm thick sample. The yellowish-green color of this material comes from Fe³⁺ and particularly its Cr³⁺ content.  Data Files: E||a 22K; E||b 21K; E||c 22K  This sample shows significant dichroism on the (010) face.
• GRR 73, 4K; from Hotazel, S.W. Africa, 0.781 mm thick sample.  The pink color of diaspore from this region is due to Mn³⁺ substituting for Al.   Data files:  E||a, 34K; E||b (not available); E||c, 34K.

Link to a collection of references to mostly color and visible spectroscopy of diaspore

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