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Star or asteriated quartz


#1

Quite a few years ago I used to collect and cut asteriated quartz. I
had put the rough and cut specimens away until recently, but have
become interested in the material again. A collector was showing me
some very nice stars in quartz from Sri Lanka that had a yellowish
background color and a very sharp and bright star. I’ve cut stones
from all varieties of rose and lavender quartz and have specimens of
blue, white, colorless and smoky-gray tints in my collection. I have
not observed the yellowish quartz before. Can anyone shed some light
on this material. Locality? Any sources? Cause of color? Probable type
of inclusions that are causing the star? All help or suggestions
welcome.

Henry Barwood


#2

Hello Barwood, check out the “Gem King” web site for green neon
quartz I’ve seen several types of star quartz materials from varios
places, the yellow green sounds quite nice, good luck, Tom ps, I’m
not affiliated with that buisness.


#3

Henry, I have never seen t he yellow star quartz from SriLanka, but I
have seen a lot of yellow to yellow/green chrysoberyl from SriLanka.
Could it have been chrysoberyl? My next guess would be that the
quartz has been radiated. Most quartz when exposed to radiation will
turn brown or yellow. Some quartz is heated from the brown radiated
color to a yellow color. If you are interested in gemstone
treatments I would suggest the book “Gemstone Enhancements” by Kurt
Nassau, available from GIA or a local library. In my opinion this
book should be mandatory reading for anyone in the gemstone business.

Gerry Galarneau


#4

Hi Gerry, The pieces I was shown were large, relatively clear and had
a sharp six-ray star. It is highly unlikely they were chrysoberyl.
Certainly, a star chrysoberyl of that size and perfection would be
well beyond the capability of the average collector.

It is certainly possible that they were irradiated to produce the
color, but lacking almost any on the stones, it is
difficult for me to say. Thanks for responding.

Henry


#5

Gerry: Natural asteriated quartz usually has a fairly faint star. In
the old days (50’s to 60’s) the lapidary books advised backing the
stone with a mirror to improve the intensity of the star.

HTH,
Roy


#6

Mirror backing stones really brought back some memories. My first
introduction to quartz star stones was in the mid-1960’s when the
Hogg mine near LaGrange, Georgia was open to collectors for a small
fee. The rose quartz from there is essentially all asteriated, but
produces only weak surface stars. Local lapidaries would cut cabochons
and display them on a mirror where the reflected light made the stars
stand out. Later, I found out how to use beam-splitters to make cabs
with “enhanced” stars that could be backed with any color to mimic a
star sapphire, ruby, etc.

Henry