Posted 1 year ago
Labradorite [(Ca,Na)(Al,Si)4O8]
Labradorite is one of the plagioclase feldspars that lies Anorthite CaAl2Si2O8 and NaAlSi3O8. Compositionally, Labradorite is An50-An70 A. The distinctive play of colors is called labradorescence and is caused by the schiller effect: the result of light refracting within lamellar intergrowths resulting from phase exsolution on cooling in the Boggild miscibility gap, An48-An58. 

Labradorite [(Ca,Na)(Al,Si)4O8]

Labradorite is one of the plagioclase feldspars that lies Anorthite CaAl2Si2O8 and NaAlSi3O8. Compositionally, Labradorite is An50-An70 A. The distinctive play of colors is called labradorescence and is caused by the schiller effect: the result of light refracting within lamellar intergrowths resulting from phase exsolution on cooling in the Boggild miscibility gap, An48-An58

Posted 1 year ago

Grossular [Ca3Al2(SiO4)3] from Canada

Posted 1 year ago

Pyroxene in thin section with cross-polarized light.

Posted 1 year ago
Posted 1 year ago

Cheat Sheet Placemat by llot llov

Posted 1 year ago
Posted 1 year ago

mineralia: Gersdorffite [NiAsS] from Morocco

The white and green concretion at the lower right is probably an alteration product… I think that either the nickel or arsenate would cause a green color.

Posted 1 year ago
Posted 1 year ago
Posted 1 year ago