|
344 Glossary
|
||
|
|
||
|
Blebby. Blisters or bubbles in a crystal mineral
Blue Ground. Diamond-bearing clay of lower levels of South African diamond mines.
Blue White. Highest grade of South African diamonds.
Bort or Boart. Imperfectly
crystallised form of diamond unfit for gems and used for pointing rock
drills, for bearings of fine machinery and other technical uses.
Botryoidal. A surface presenting a group of rounded projections.
Breccia. A
not wholly formed rock of angular fragments naturally cemented by lime
or some other adhesive mineral substance or " binder."
Brilliant.. A style of diamond-cutting with fifty-six facets, exclusive of table and culet.
Brittle. A mineral, when it may be readily broken by a blow.
Brittle. A stone that breaks, or parts of it separate into powder, when the attempt is made to cut it.
Browns. Eighth in list of principal trade terms in grading diamonds.
Bruting. Polishing diamonds by rubbing one against another.
Bubbles. Small hollow specks in the body of a gem.
Built-up Ruby. Reconstructed ruby.
Byon. Brownish-yellow clay in which occurs corundum— rubies, sapphires, etc.
------ Ground adjacent to mother rock in which rubies
have weathered out.
Byssus. Fibres, flaxy or silky in appearance, by which a mussel attaches its shell to wood or stone.
By-Waters. Yellow tinted diamonds.
Capes. Diamonds with a yellowish tinge.
Capillary. Hair-like.
Carat. (Karat.)
A unit of weight applied to precious stones verying in different trade
centres. See table of weights of the carat in various localities in the
Appendix.) The word carat is supposed to be derived from " Kuara," the
bean-like fruit of an African tree reputed to have been used as a
standard of
|
||
|
|
||