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This list digest contains the following message subjects:
1. LapDigest News for Issue No. 26 Monday, 14 Jul 1997
2. RENEW: Polishing Corundum (Was 2-4)
3. RENEW: Tiger-eye Treatment (Was 13-1)
4. RENEW: Orienting Rainbow Obsidian (Was 20-2)
5. NEW: Aussie Opal Cracking
Subject: LapDigest News for Issue No. 26 Monday, 14 Jul 1997
While working on the Index to the Archives, I noted that there were several
queries which had been posed but had never been answered. With a larger
number of subscribers, it is likely that someone will know the answers
to some or most of them. So it's RECYCLE time!!! We recycle 3 of the 5
unanswered queries below; since they are really not NEW, they are now
titled RENEW. Can anyone give answers to them?
All items today are either NEW or RENEW ones; there were no responses
to past queries. This brings up this point: if we don't have enough items
to fill a decent LapDigest issue, it wont go out that day. So if you don't
get one some day, start contributing! (smile)
Subject: 2. RENEW: Polishing Corundum (Was 2-4)
I have just cut my first Corundum (Star Sapphire and Star Rudy cabochons).
I am happy with the placement of the stars in the cabochons. The problem
is I'm not happy with the final polish. This is the hardest material I
have cut to date, is there a secret to obtain a high polish? My stages
were: 220, 280, 600, 1200, 8000, 14000 & 50000 grit (all diamond).
Under water the stones look great.
Do I need to go to 100000, or perhaps I'm just moving too fast through
the final stages (but how do I tell?)? Any suggestions would be greatly
appreciated. Thank you.
Subject: RENEW: Tiger-eye Treatment (Was 13-1)
I've seen nice catseyes produced from tiger-eye. I understand they use
acid to lighten the tigereye to the light honey color. Oxalic acid might
be the acid. Is someone familiar with the exact process?
Subject: RENEW: Orienting Rainbow Obsidian (Was 20-2)
I have a large chunk of Rainbow Obsidian rough. I have been told that
there is a special technique to cutting Rainbow Obsidian to produce a
heat rainbow design instead of a a circular rainbow. It was explained
to me once but I have forgotten the directions. Can anyone help with this.
Geri Arms <DEZIGNS@mwci.net>
(How about any info on orienting Rainbow Obsidian? -hale)
Date: Tue, 15 Jul 1997 10:28:19 +1000
Subject: NEW: Aussie Opal Cracking
Cracking can be a problem with opal from certain opal fields here in Australia.
Minatabie Opal in certain areas can crack badly after only one year. But
the miners know what level it is that produces opal which cracks. The
opal from that level is very cheap unless you are from overseas sort of
thing. The genuine miners there will tell you that it cracks and the majority
wil not even sell it to you!!. It simply gives the field a bad name.
It is the overseas buyers who ask for that opal most often, those who
large market to sell to and do not care who they hurt. The high grade
stones from Minatabie are just that very high grade and I have never seen
one crack or craze, the same is true with Coober pedy opal.
I love working with Yowah Opal with an Ironstone backing and the opal
intertwined around the ironstone or black Hematite. It produces the most
beautiful of stones and everyone is unique in pattern. (We are mining
of this material at present if anyone is interested and have some lovely
parcels available between $500 to $9000 US dollars. You can view these
our web site at http://www.ozemail.com.au/~cstone/ )
I have never seen Yowah opal craze or crack unless I have dropped it,
which often happens (not using a dop stick). The predominant colors are
Green/Blue and Purple. The rarest color in this type of opal is red, and
it commands a 5 to 10 fold price increase as a general rule.
But well worth cutting. We cut these stones using only diamond equipment,
otherwise it can chip out from the ironstone; the diamond tends to stop
this from happening. Final finishing wheels, after the 100 diamond, are
nova wheel, then a 1200 nova wheel, then a 14,000 nova wheel. Polish using
titainimum oxide on soft felt or 100,000 diamond on leather with a
little oil gives a great finish.
I have a few of the stones cut for you to see on our hand-cut opal web
if interested. Hope this helps
Tanzanian Gemstone Rough Direct Mine Prices
Australian Opals Rough & Cut At Wholsale Prices
Australian Rough & Cut Sapphires
Web Site: http://www.ozemail.com.au/~cstone/
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