[Jewelry making - Article 00289] - Re: [Orchid] Material adhering to gemstones

[John Donivan]

========[ Invite a Friend - http://www.ganoksin.com/invite.htm  ]========

>     I will get a sapphire or emerald that has collected a film on its
>     surface that defies normal cleaning practices 

    Jefffrey - There is a phenomenon called variously, but usually boric
    acid etching, but it can't be on emeralds. When someone retips or
    solders on or near corundum, and uses a boric acid dip like usual,
    the boric acid can etch the surface of the stone under heat. The
    more heat, the more likely it will occur. The effect is just as you
    describe - often it looks like motor oil on the surface of water,
    the pattern of it. Sometimes if it's light tripoli will dress it up,
    but only refinishing the surface will truly remove it. I suspect
    that you are seeing that at times, and other things at other times.
    It can't be on emerald because you can't heat them and it only
    happens on corundum. It's pretty common though, because less
    experienced repair people don't know, and then they think it's just
    tenacious dirt or don't see it at all. If you're heating corundum
    just don't put boric acid or wipe it off the stone before heating it
    - corundum doesn't need the coating anyway. 

http://www.donivanandmaggiora.com
____________________________________________________________________
T h e   O r c h i d   L i s t
Open Electronic Forum for Jewelry Manufacturing Methods and Procedures
____________________________________________________________________
Orchid FAQ:
~ http://www.ganoksin.com/orchid/faq.htm
Orchid Archives:
~ http://www.ganoksin.com/orchid/archive
Orchid Galleries:
~ http://www.ganoksin.com/orchid/gallery.htm
Invite a Friend:
~ http://www.ganoksin.com/invite.htm
____________________________________________________________________
Tips From The Jeweler's Bench - Article Archive
~ http://www.ganoksin.com/borisat/tip_sear.htm
The Jeweler's Selected Bibliography List
~ http://www.ganoksin.com/jewelry-books
Buy Orchid Jewelry:
~ http://www.ganoksin.com/shop
____________________________________________________________________
-Unsubscribe:
-Email: orchid-request AT ganoksin.com Body=unsubscribe subject=blank
____________________________________________________________________