Chrysolite Group

The chrysolite group is an important one at Franklin. It includes the manganese olivines (tephroite and roepperite), the calcium tephroite (glaucochroite), and the recently described lead-bearing members of the group (larsenite and calcium larsenite). Their relations of composition and form are shown in the following comparative statement.

**Comparison of members of the chrysolite group**
Species	Composition	Axial ratio a : b : c	Specific gravity
Tephroite	(Mn,Mg,Zn)₂SiO₄	0.461 : 1 : 0.589	4.12
Roepperite	(Fe,Mg,Mn,Zn)₂SiO₄	0.466 : 1 : 0.586	4.00±
Glaucochroite	CaMnSiO₄	0.441 : 1 : 0.581	3.41
Larsenite	PbZnSiO₄	0.434 : 1 : 0.532	5.90
Calcium larsenite	(Pb,Zn,Ca)SiO₄	Unknown	4.42


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