Oxyhornblende (Lamprobolite, Basaltic Hornblende)

Ca,Mg,Fe,Al silicate, an amphibole

Optical Properties:

Biaxial -; 2V 60-80 degrees; yellow to reddish brown pleochroism; amphibole cleavage; extinction angle close to 0 degrees. Pleochroic colors are distinctive.

The photograph above shows phenocrysts of lamprobolite in andesite.

Occurrence:

Volcanic rocks such as andesite and others.

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