Adamantine. Very hard—as hard as steel. From Adamas (Greek); Adamanta (Latin), the lustre of the diamond.
Aggregates. Clusters or groups.
Alluvial. Washing away rocks, soil, or other mineral material from one place and depositing the débris in another.
Amorphous. Without form, shapeless.
Amulet. From hamalet (Arabian), to carry. A charm, or talisman, worn on the person to ward off disease, accident, or other harm.
Arborescent. Resembling a tree in appearance.
Asteriated. Radiated, with rays diverging from a centre, as in a star—as exhibited by an asteriated or star sapphire.
Aviculidae. Wing-shells, or Pearl Oysters.
Axis. Axes or planes of crystals or other minerals—as demonstrated in crystallography.
Baby. Trough or cradle in which gravel was washed for diamonds by early South African diamond-seekers.
Bahias. Diamonds from the Bahia district, Brazil.
Foundation price of a one-grain pearl from which to reckon prices of
pearls of other weights. The price of pearls is quoted by the grain and
reckoned by the square; example: a two-grain pearl at three dollars
base would be twice three dollars, or six dollars per grain 'flat'; and
two grains at six dollars would be twelve dollars, the cost of the
pearl.'" (From Precious Stones by W. R. Cattelle.)
Birefringence. Double refraction of light of crystal minerals.
Bizel. Portion of brilliant-cut diamond above the girdle.