All About Jewels: Illustrated Dictionary of Jewelry

RADIANT CUT The radiant cut is a method of cutting rectangular stones so that they have 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; it was invented in the 1970's. The top of the stone is emerald cut (with about 25 facets above the girdle), but the bottom of the stone has brilliant cut facets (with about 36 facets below the girdle).

RAINBOW CALSILICA Rainbow calsilica is a newly-found, multi-colored, layered stone composed of calcium and silica. This stone has been recently used for Zuni fetish carvings and in some jewelry (beads and cabochon cut stones). Rainbow calsilica was only recently found in Mexico or Northern South America (it's origin remains mysterious). Some people theorize that this stone formed as a result of the runoff of mining or oil-drilling chemicals, and has only formed in the last 30 to 50 years (but this is uncertain).

RAINBOW OBSIDIAN Rainbow obsidian is another name for obsidian that is iridescent.

RAINBOW OPAL Rainbow opal is a type of precious opal that has curved bands of colors (that resemble rainbows).

RAINBOW TOPAZ Rainbow topaz (also called mystic topaz or mystic fire) is topaz that has been color enhanced by coating it with a fine layer of metal atoms (in a process called vacuum deposition). This stone has red, green, violet, and blue streaks. Mystic fire has a hardness of 8.

RAJARATNA The Rajaratna is the biggest-known "star ruby" (a ruby that exhibits an asterism, a six-pointed star of light, cut as a cabochon). It weighs 2,475 carats.

REFRACTOMETER A refractometer is a device that measures the refractive index of a gemstone.

REGARD Regard jewelry uses the stones Ruby, Emerald, Garnet, Amethyst, Ruby, and Diamond to spell the word "REGARD." Regard jewelry was given as a token of affection. This sentimental style was popular during the Victorian era.

RENOIR OF CALIFORNIA "Renoir of California" is a US jewelry company that makes copper jewelry. Their line marked "Matisse" is enameled copper; their line marked "Renoir" does not have enamel. The enameled copper leaf pin above is marked Matisse adn was made by the "Renoir of California" company.

REPOUSSE Repousse is a method of decorating sheet metal in which designs are hammered into the back of the metal. Special punches are used to form the designs, which form in relief (raised designs) on the surface of the metal.

RETRO Retro jewelry is chunky, geometric jewelry from the 1940's. Pink gold was often used in retro pieces.

REVERSE-CARVED LUCITE Reverse-carved lucite is lucite (a transparent plastic) that is carved on the back side. The incised areas are often painted, highlighting the carving. The pin pictured above is clear, reverse-carved lucite that is accentuated with yellow and green paint; the painted carving closely resembles tiny roses.

RHINESTONES Rhinestones are highly reflective glass made to imitate gemstones. The original rhinestones were quartz stones (rock crystal) obtained from the Rhine river. These stones were cut to resemble gemstones. The best rhinestones today are made of highly reflective leaded glass which is faceted and polished. The Trifari pin above has baguette cut and round cut rhinestones.

RHODIUM Rhodium is a white precious metal. Rhodium is extremely expensive and is often used to plate precious and base metals, giving jewelry a hard, platinum-like sheen.

RHODOCHROSITE Rhodochrosite is a mineral whose color ranges from rose to pink to almost yellow or brown. Although it is very pretty, this stone is soft and brittle; it is used in jewelry and for carvings and figurines. Rhodochrosite is Manganese Carbonate; its chemical formula is MnCO3. Rhodochrosite has a hardness of 3.5 - 4.5 (glass has a hardness of 4) and a specific gravity of 3.5. Rhodochrosite is found in Argentina, Peru, Germany, Mexico, South Africa, Russia, Italy, USA (Colorado and Montana), and Romania. Rhodochrosite is not enhanced.

RHODOLITE Rhodolite (meaning "rose stone" in Greek) is a purple-red to pink-red variety of garnet. It is a combination of almandine and pyrope (it is sometimes called pyrope-almandine garnet). This silicate stone has a hardness of 7-7.5 and a specific gravity of 3.5 - 4.3. The formula for garnet is: A3B2(SiO4)3. Rhodolite is found in the US, Zimbabwe, Kenya, and Sri Lanka (Ceylon). Rhodolite is not enhanced.

RICHELIEU Richelieu jewelry is made by Joseph H. Meyer Bros. company of Brooklyn, N.Y. THe Richelieu name was first used in April, 1911. Richelieu manufactures clips, rings, necklaces, bracelets, and other costume jewelry.

RING A ring is a piece of jewelry worn around the finger; rings have been worn on every finger, including the thumb. Rings have been worn through the ages, and often have significant meaning. Some rings include wedding and engagement rings (denoting commitment), signet rings (impressed with the owner's seal), bands (made from a ribbon of metal), rings denoting group membership (like Masonic rings or college rings), devotional rings (with religous meaning), and pugilist rings (pointed rings worn by boxers to harm their opponent).

RING SIZE Rings are sized using a graduated cone (a mandrel) with markings denoting the ring sizes. The ring is put on the cone and its size is read where it fits snugly on the cone. To size a finger, a finger-ring gauge is used. The rings are marked with their size and the person determines which one fits well. Another, less accurate method, is a cardboard card with cut-out holes marked with the ring sizes. Sizes in the US and Europe are numerical; sizes in the UK are alphabetical. To determine the ring size of a finger using the circumference of the finger, or to determine the size of a ring given its diameter, the formulas are: System Formula using Circumference Formula using Diameter USA Circumference in mm = 36.107 + (2.5890*Ring Size) Diameter in mm = 11.4931 + (0.8241*Ring Size) Europe Ring Size =Circumference in mm Ring Size = 3.1416 * Diameter in mm UK Circumference in mm = 36.667 + 1.2368*Ring Size(where 1=A, 2=B, etc.) Diameter in mm = 11.6713 + [0.3937 * Ring Size(where 1=A, 2=B, etc.)]

RIVERSTONE Riverstones are smooth, rounded pebbles found in rivers and on beaches. The action of the water and other rocks on riverstones polishes them naturally. Riverstones can be used as beads/stones in jewelry.

ROBERT "Robert" and "Original by Robert" were costume jewelry marks used by the Fashioncraft Jewelry Company (founded by Robert Levey, David Jaffe, and Irving Landsman in the 1942. These high-priced, hand-made pieces are often complex, having beads and pearls, rhinestones, enamel, and/or floral designs; they are often similar to some Miriam Haskell pieces. Robert jewelry was used in some Hollywood films, including the 1952 movie "Viva Zapata." Robert pieces were produced until around 1975.

ROCAILLE Rocaille is jewelry whose design is based on sea life, sea shells, or rocks.

ROCK CRYSTAL Rock crystal is a transparent, crystalline mineral. Rock crystal is the purest form of quartz and a semi-precious stone.

ROCKY MOUNTAIN RUBY A Rocky Mountain ruby is actually a pyrope garnet (and not a ruby at all).

ROLLED GOLD Rolled gold is a very thin sheet of gold that is laminated to a lesser 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. Jewelry made from rolled gold wear well over time. Rolled gold pieces are marked rolled gold plate, R.G.P., or plaqué d'or laminé.

RUBELLITE Rubellite (sometimes spelled rubelite) is a red variety of tourmaline. Rubellite is red in both incandescent light and daylight, and is more valuable than other varieties of red tourmaline. Rubellite 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.

RUBY Rubies are precious stones and a member of the corundum family (Al2O3). Rubies range in color from the classic deep red to pink to purple to brown. Rubies are extremely hard; only diamonds are harder. During the renaissance, people thought that rubies could counteract poison. Laboratory-produced rubies were created in the 1890's; they are difficult to distinguish from natural rubies. The biggest ruby in the word is the Raviratna, which weighs 3,600 carats. 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 (Ceylon), Tanzania, Thailand, United States, and Zimbabwe (Rhodesia).

RUBY SPINEL A ruby spinel (or spinel ruby) is deep red, transparent spinel (not a ruby).

RUMANITE Rumanite is a type of opal that is from Romania.

RUSSIAN GOLD FINISH A Russian gold finish is a matte, antique-look finish. Miriam Haskell jewelry often has a Russian gold (plated) finish.

RUTHENIUM Ruthenium (abbreviated Ruth or Ru) is a precious metal that belongs to the platinum group of metals. In jewelry, ruthenium is added to platinum alloys; about 5 to 10 perent ruthenium can be added to platinum to harden and strengthen the alloy. Ruthenium's atomic number is 44.

RUTILATED QUARTZ Rutilated quartz is a type of rock crystal which contains long, fine needles of rutile crystals (titanium dioxide). This beautiful stone is usually cut as a cabochon. It is also known as Venus' Hair Stone, Cupid's darts, and Fleches d'amour (arrows of love).

All About Jewels: Illustrated Dictionary of Jewelry

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