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Radiant cut
A method of cutting
rectangular stones to give them the sparkle of brilliant cut
round stones. The shape is a rectangle with the corners clipped
off – the length: width ratio is usually from 1.5:1 to 1.75:1.
This cut has from 58 – 70 facets.
Rainbow opal
A precious opal that
has curved bands of colors looks like a rainbow, hence the name.
Reconstructed stone
Stone formed with the pieces of smaller stones or crystals.
Reconstructed stones often have telltale air bubbles, these are not manufactured
nowadays (except superior to reconstructed amber, which is still made)
because synthetic stones are vastly superior to reconstructed
stones.
Red Beryl
A variety of beryl that is rare and deep red
in color. Gemstone-quality forms of this mineral are found in only
one place in the world, in the Wah Wah Mountains, near Beaver,
Utah, USA. The biggest
red beryl crystal over found was 14mm by 34mm, weighing about 54
carats. Red beryl has a hardness of 7 – 8, a specific gravity of
2.66 – 2.70, and a refractive index of 1.564 – 1.574.
Refraction
A process in which the light bent at an
angle and change its speed when it enters a medium with a different
optical density, like in gemstones.
Refractive index
An index that shows the measure of how
light is refracted in a substance (like a gemstone). There are
some stones that have doubly
refractive property, in such stones, the light is split into two light rays when it
enters the stone, and the rays travel in different paths – so
these stones have more than one refractive index.
Refract meter
It is a device that measures
the refractive index of a gemstone.
Rhodochrosite
A mineral comes in color
ranges from rose to pink to almost yellow or brown. This pretty,
but soft and brittle stone is used in
jewelry and for carvings and figurines.
Rhodolite
known as rose stone in Greek, it is a
purple-red to pink-red variety of garnet and is a combination of
almandine and pyrope, hence also sometimes called pyrope-almandine
garnet. This silicate stone has a hardness of 7-7.5 and a
specific gravity of 3.5 – 4.3.
Ring
A very common and popular jewelry piece worn around the
finger. Rings can be worn in any finger including the thumb. Rings have been worn through the ages, and often have
significant meaning. Some rings include wedding and engagement
rings, signet rings, bands, rings
denoting group membership,
devotional rings, and pugilist rings.
Rolled Gold
A very thin sheet of gold
that is laminated to an inferior metal (usually brass). The two
layers of metal are heated under pressure to fuse them together.
The sheet is them rolled into a very thin sheet and then used to
make jewelry or other objects. s
Rondelle
A small disc that is used as a spacer
in beadwork. Some rondelle are clear crystal discs, and others are encircled with
channel-set diamonds or rhinestones.
Rope
A string of pearls that is over 40
inches long.
Rose Cut
It is a style of diamond cutting that is
also known as rosette cut. The rose cut has a flat base and
triangular facets (usually 24).
Rose quartz
A form of quartz that ranges
in color from pink to deep red.
Rough
Term used for raw stones or crystals that are in their
natural state, neither cut nor polished.
Ruby
Precious stones from the corundum family. Rubies
are found in colors ranges from the classic deep
red to pink to purple to brown. Rubies are second in the hardness
after diamonds. Rubies have a hardness of 9 and a
specific gravity of 3.9 – 4.1 Rubies are found in Afghanistan,
Australia, Brazil, Cambodia, India, Myanmar (Burma), Malagasy
Republic, Malawi, Pakistan, Sri Lanka (Cylon), Tanzania,
Thailand, United States (Montana and North Carolina), and
Zimbabwe (Rhodesia).
Russian Gold Finish
A pattern of finishing in which the metal
has a matte, antique-look finish.
Rutilated Quartz
A rock crystal
that has long, fine needles of rutile crystals. Alos known as
Venus’ Hair Stone, this is a beautiful stone usually cut as
a cabochon.
Rubellite
Rubellite or rubelite is a
red variety of tourmaline that is more valuable than other varieties of red
tourmaline. It has a hardness of 7-7.5 and a specific
gravity of 3.02-3.25. Rubellite is sometimes treated with fillers
to increase the clarity of the stone.
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