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Clinohumite or clinochere


#1

Anyone have Info on probable gemstone (clinohumite or clinochere)

I found a box full of cut faceted gemstones i put away maybe 30+
years ago, marked “uzbek.”, “kush mtns.” and “nepal” on it. They
still look great a nice orange-red to red-orange and some with a band
of yellow-orange around the perimeter of deep red on some pear and
kite cut stones. no rounds, ovals or ordinary cuts. so i apparently
had plans for them, Just don’t recognize them whatsoever. I am
wondering if anyone has used them- and beyond their hardness (which I
had labelled 6-7 on the box) I would like any other info you can tell
me about them. They seem soft and maybe I can regrind them into other
shapes since some are too large for anything I’d make these days…

If you do know anything about faceting them, meet point is how I’d
approach them. but if they cleave easily perhaps there is a better
way to approach re-cutting or grinding They have a “petroline” like
luster so oiling seems out. any suggestions appreciated… rer


#2
If you do know anything about faceting them Clinohumite, from
Vargas: 

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
Trichroic
RI 1.63
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
Pleochroic
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


#3

Thanks Al. sounds tricky. ans like they may just stay the shapes
they are. I looked at a few with light passed through them- some
gorgeous pieces. one. orange outlining the gradiating to cherry red
coloured in the heart of the trillion. and a marquise that looked
like a confetti of dark red, red, orange, orange-red and pink with a
few bits of yellow as an accent. like a harlequin opal without the
clear, spectral quality and lightness (weight) opals have. just
gorgeous…’ Thanks too Lorraine, I hadn’t even thought of the
faceter’s guild…(and after Al’s info, maybe someone would want to
"practise" on some in exchange for a few.!..who knows…) anyway,
great idea…

Best regards, R. E. R