If you do know anything about faceting them Clinohumite, from
Hardness 6 to 6 1/2
Specific Gravity 3.17 to 3.35
Cleavage poor, one axis
Fracture conchoidal to uneven, brittle
Heat sensitivity low
Critical angle 38 degrees
Suggested cutting angles pavilion 43 degrees, crown 41 degrees
Very brittle, use fine or extra fine cutting lap, polish with
alumina at slow speed.
Clinochlore is completely different.
Hardness 2 to 2 1/2
Specific gravity 2.55 to 2.75
Cleavage perfect, one axis
Fracture uneven, very brittle
RI 1.631, 1.64, 1.668 on the three axes
Critical angle 39.6 degrees
Even Vargas has no suggestions on cutting clinochlore, but it
doesn’t sound easy from the physical characteristics.
– Al Balmer Pine City, NY