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ruberite

See:cuprite

rubicelle

A yellow or orange-red variety of spinel; an aluminate of magnesium.
CF:ruby spinel

rubidium

A soft, silvery-white, metallic element of the alkali metal group, closely
resembling potassium. Symbol, Rb. Widely distributed in small quantities
in nature. Obtained commercially from lepidolite and from potassium
minerals. Forms amalgams with mercury and alloys with gold, cesium,
sodium, and potassium. Has been considered for use in space vehicles, and
for use in thermoelectric generators. Handbook of Chemistry and Physics, 3

rubinblende

Miners' term for the red silver sulfides pyrargyrite, proustite, and
miargyrite. Syn:ruby blende

rubinglimmer

See:lepidocrocite

Ruble hydraulic elevator

A device by which coarse material in placer gravel is separated from the
fines and elevated onto a dump.

ruby

The red gem variety of corundum, the color due to the presence of chromium
in the structure. CF:sapphire

ruby alumina

An abrasive similar to white alumina except ruby red in color because of
the presence of chromic oxide. ACSG, 2

ruby arsenic

An early name for realgar. See also:ruby sulfur

ruby blende

a. A reddish variety of sphalerite. Syn:ruby zinc
b. See:rubinblende

ruby cat's eye

A girasol ruby with a chatoyant effect. CF:sapphire cat's eye

ruby copper

See:cuprite

ruby copper ore

See:cuprite

ruby mica

An old syn. for goethite. Fay

ruby sand

A red-colored beach sand containing garnets, as at Nome, AK. AGI

ruby silver

Dark ruby silver is pyrargyrite, and light ruby silver is proustite.
Dana, 4

ruby spinel

A red gem variety of spinel. CF:almandine ruby; balas ruby; rubicelle.

ruby sulfur

See:realgar
Standard, 2; Fay

ruby tin

A red variety of cassiterite.

ruby zinc

Miners' term for transparent red sphalerite or zincite.
Syn:ruby blende

rudaceous

Said of a sedimentary rock composed of a significant amount of fragments
coarser than sand grains; pertaining to a rudite. The term implies no
special size, shape, or roundness of fragments throughout the gravel
range, and is broader than pebbly, cobbly, and bouldery. Also said of the
texture of such a rock. AGI