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Bending Black coral

I bought black coral in Tucson and was told by the dealer that I
could bend it. He mentioned a JCK article in the last year or two
that instructs how to do this. I cannot find the article. Does
anyone out there know how to bend black coral?

Thank you,
julie simpson


It depends a lot on the kind of black coral you purchased. For
further on Gorgonian black coral, see my articles in the
August, Sept, and Dec 2000 issues of the Lapidary Journal. I have
been working with black coral for over 10 years and also teach
workshops twice a year on how to make jewelry with it at the Boca
Raton Museum of Art School in Boca Raton, FL.

My articles describe the nature of black coral and the two kinds you
will find; antipatharian and gorgonian…the first being deep water,
the second shallow water. They also discuss the nature of each, how
to collect coral, the legal aspects of doing so, how to clean, polish
and form (bend) and how to make various items such as knots, beads,
etc. After reading the articles, if you need more let me
know and I will supply it.

Cheers from Don at The Charles Belle Studio in SOFL where simple
elegance IS fine jewelry!



  Black coral is almost woodlike. It is fibrous and has growth
  rings like a tree. It's not that rare. It grows in the channels
  off the Hawaiian Islands, around the Phillipines and Indonesia
  and probably other Pacific Islands. The stuff around Hawaii is
  in deep water, 100+ feet and takes skilled diving to harvest. 
  It has to be dried for months before it can be cut. We wait a
  minimum of 6 months. 

  The thin branches can be soaked and bent. You can bandsaw the
  coral and cut cabochons quite easily. You can shape it with
  files (dulls them), grinding wheels, belt sanders, diamond
  burs, saws, assorted steel burs, sanding discs, etc.  You can
  progressively sand and then polish or you can hit it with
  bobbing compound if you like.  It polishes to a shiny surface
  with yellow rouge.( Note: You can burn the coral if you let too
  much friction build up.  The burnt coral behaves like burnt
  wood.  It discolors and doesn't polish well.) 

  Depending on the way the coral grew, you can have different
  densities, knotholes, gaps between the growth rings, imbedded
  shells, etc.  Sometimes, you can not achieve a fine polish
  because the coral "orange peels" or has a coarse grain.  Also,
  the outer "skin" is rough to the touch like sharkskin so you
  would want to remove the outer skin before doing any bending
  and forming of branches into bracelets. 

  The coral is absorbent so you don't want to soak it or expose
  it to chemicals and perfumes. Like polished wood, it scuffs and
  scratches. It can shrink even after prolonged drying/curing if
  exposed to hot lights. 

  In Hawaii, the harvesting is regulated.  Stumps have to be a
  certain diameter and you can't dredge for coral. You have to
  dive and selectively harvest. The same can't be said for other
  parts of the world. 

  Donna Shimazu