Standards Block: Glaucophane

Questionable

NOTES: Reasonably big glaucophane crystals, but very inhomogeneous as can be seen especially on the bottom-left BSE image. This sample has at least 5 phases.

Position	83
Mineral	Glaucophane
Sample Name	Glau
Type	Amphibole
Nominal formula	[ ]Na2(Mg,Fe)3Al2Si8O22(OH)2
Supplier	Cannon Microprobe, Seattle, WA
Source	Mark West Springs, Sonoma Co., CA
Original reported analysis	–
Composition quality	Questionable
Comments	Fine-grained intergrowth of several things. Probably the majority of the lower grain is actually glaucophane, but it’s quite zoned.