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How heat sensitive is a lindy star?


Hi all, I have a customer that has a lindy star sapphire mans ring.
It needs a new shank and he wants to add a couple of diamonds to the
sides, my question is, how heat sensitive is a lindy star? I could
recommend a new setting if the heat would destroy the Lindy. Thanks,
Janine in Sunny at last Redding CA,


Hi Janine, Heat will not destroy a Linde. Let it cool slowly and you
should be fine. Really, really slowly. Have fun. Tom Arnold


Hi Janine, in my experience heating the Lindy is a 50/50 proposition.
The last one I heated on didn’t take it. They’re cheap enough to
gamble on trying to heat sink it, so I’d consider the setting of the
stone first. If it’s prong set, pull it, if not, give it a shot and
replace it if necessary.

Mike Rogers
Precious Metal Arts


My understanding is that sapphire will withstand the heat of casting.
so I beilieve that it would be fine for soldering. Then again, I
have heard of jewelers who remove all stones during soldering just to
be safe. Michael


My husband, a gemologist, says that most sapphires are heat treated,
and it’s best not to heat them …Char

Ms. Charolette's Gold & Gem Specialties LLC
Rob & Charolette Purviance Jr.
115 N. 2nd Street
Guthrie, OK. 73044

(405)-260-0613 store
(405)-260-0638 office
(405)-260-0634 fax


Much learning does not teach understanding… Heraclitus C. 540- C.
480 B.C.


Linde stars are grown much the same as their natural counterparts.
The star comes from the rutile crystals within the sapphire. The
rutile will melt at around 1700f whereas the sapphire should holdup to
around 3000f , so if your process involves temps over 1700f then you
may have a problem.


   My husband, a gemologist, says that most sapphires are heat
treated, and it's best not to heat them 

True. But Linde stars are synthetic star sapphires, not naturally
occuring ones. They are made using a variation of the old flame
fusion technique. Made simply in the color desired. an
annealing/reheating step allows the rutile to come out of solution,
forming the star. Not actually a conventional “heat treat” such as is
used to color enhance most natural sapphires. Still, many of these
stones are under some internal strain, and they can crack more easily
than the synthetic transparent ones. I don’t recommend heating them
unless you’ve got no choice. On the other hand, they’re a lot cheaper
than natural ones, and sometimes it’s not that big a financial risk to
heat it, if it’s cheaper to risk that than taking it out for some
reason. Just be aware that it’s a risk, and be sure you’ve got a
source for a replacement if needed (and the owners permission to take
that risk).

Peter Rowe G.G.

   My husband, a gemologist, says that most sapphires are heat
treated, and it's best not to heat them

As far as I know,starssapphires are not heat treaded due to the fact
that the heat treading proces is improving the color of clear
stones.Since starsapphires are not clear at all they’re not a subject
of changing there color.By all means, that’s what I know from the
books that I have,but I’m not a gemmologist.