Glauconite KMg(Fe,Al)(SiO3)6.3H2O

Optical Properties:

Biaxial -; 2V 16-30 degrees; green to yellow pleochroism; excellent single cleavage; parallel extinction; often forms in pellets in sediments.

Occurrence:

Glauconite forms under reducing conditions in sediments and is commonly found in nearshore sandstones.

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