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| Word |
Description |
| O.E.W.S |
Old English Wine Standard, the most commonly used standard for liquid measure in England during the 17th, 18th and early 19th centuries. It was used in the American colonies as well and continues in use in the U.S. to the present time. However, the United Kingdom adopted the Imperial Standard in 1826. |
| O/D |
Overdrive. An extra gear or three, normally engaged by flicking a switch. Available on older cars |
| Objects of Virtu |
Small luxury items such as snuff boxes, mulls, vinaigrettes, necessaires, seals and needle cases. Often made of silver, as well as gold, tortoiseshell, porcelain and enamel. |
| Octahedral |
A geometric object with eight plane surfaces. |
| Ogee |
A bowl, foot or molding form, its profile in the shape of a double curve like an elongated S. |
| OHC |
Overhead camshaft – A more efficient engine design. Almost all cars have them nowadays |
| Oiling |
The process of applying mineral oil to a stone, such as an emerald, to mask inclusions and enhance the color. |
| Old European Cut |
A round Brilliant cut with 58 facets, similar to the old mine cut, first appearing in around the 1880's. It is characterized by a deep pavilion, high crown, and an open culet. |
| Old Mine Cut |
Mine Cut: Differs from the modern Brilliant cut only in its girdle shape, which is square instead of round, a higher crown, smaller table, deeper pavilion, and larger culet, but the number and arrangement of the facets are the same. It is lumpier than the form accepted today. This form of cut surfaced in the early 1800's and began to disappear around the turn of the 20th century. |
| Oligoclase |
(Also called Plagioclase) A triclinic feldspar made of soda-lime. |
| Olivelia Shells |
A kind of seashell used for Heishi necklaces. |
| Olivine |
Chrysolite: (Also called "olivine" and "peridot") A mineral composed of silica, magnesia, and iron sometimes used as a gem. Chrysolite ranges in color from a light pea green to a deep olive green and an oily shine. It is common in certain volcanic rocks and meteorites. Mystics have claimed that this lustrous green stone drives away evil and has special healing properties. The name chrysolite has been used in the past for yellow varieties of tourmaline and topaz. |
| Omega Back |
These work a bit like lever back earrings, in that they have a hinged lever on the back of the earring near the bottom, but in this case the lever ends in an O shape that closes over a post in place of a clutch to secure the earring to a pierced ear. |
| Omega Chain |
Unlike most chains which are a series of linked rings, an Omega chain is made up of rectangular smooth rounded metal plates set side by side and crimped along the ends onto a strip of metal mesh. The end result is a fairly stiff, yet flexible, circle which needs to be worn high around the neck since it is not nearly as attractive when viewed from the edges. |
| Onyx |
A semiprecious variety of chalcedony quartz that is a used often in jewelry. When chalcedony is variegated with with spots or figures, or arranged in differently colored layers, it is called agate; and if by reason of the thickness, color, and arrangement of the layers it is suitable for being carved into cameos, it is called onyx.
White Onyx, a semi-translucent white to slightly yellowish-white stone, was often used as a background in Victorian jewelry, especially for cameos. Black Onyx can appear opaque or translucent. Although it occurs naturally in black, it is generally dyed black to improve its color. It has a hardness of between 6.5- 7 on the Mohs scale. In India, onyx necklaces are thought to cool feelings of love. |
| Opal |
An amorphous non-crystalline variety of silica which is softer and less dense than quartz. Opals are known for their distinctive iridescent luminous qualities which are actually inclusions that can refract light in a rainbow of colors, called "fire", that change with the angle of observation (Dichroism). Opals contain a large amount of water and susceptible to cracking. Opal is the birthstone for October. |
| Opaque |
A substance which is not transparent or translucent. i.e. a substance that does not allow light to pass through it. |
| Open-work |
A setting that has open areas similar to filigree cut which may allow for viewing of the bottom of a stone. See Basket. |
| Opera Length |
A necklace which is 48 to 90 inches long. |
| Optical Properties |
A gemstone's inherent ability to interact with light. Color, dispersion and fluorescence are all optical properties. |
| Orb |
A part of coronation regalia placed in the left hand of the Sovereign during the coronation as a symbol of Kingly power. It is a globe of gold encircled by a band edged with pearls and set with rubies, emeralds and sapphires, joined by a perpendicular band and surmounted by large amethyst above which is a jeweled cross. |
| Ore |
A metal bearing mineral from which metal can be profitably mined or extracted. |
| Oriental Pearl |
A pearl that has formed naturally with no human intervention. |
| Ormolu |
A term referring to gilded bronze or brass mounts. From the French for "ground gold" |
| Orthoclase |
A variety of feldspar, composed of potassium aluminum silicate, characterized by a monoclinic crystalline structure and found in igneous or granitic rock. Also called potash feldspar. |
| Ouvarovite |
Uvarovite: An emerald green garnet composed of chromium lime. Named from the Russian Count Uvaroff. Uvarovite is almost never used as a gemstone. Distinguishing Uvarovite and Tsavorite is difficult, but an experienced gemologist can do it. |
| Oval Cut |
A "fancy cut" diamond or stone in an elliptical shape like an oval. |
| Overlay |
The upper layer of an overlay technique. The layer with the design. |
| Overlay Technique |
A decorative technique involve two flat pieces of silver, or other metal. The top piece has a design cut out of it and is highly polished. The bottom layer is darkened with oxidation to provide good contrast to the design on the top piece when the two pieces are soldered together. |
| OVNO |
or very near offer |
| Oxidation |
Essentially a silver tarnish that adds accented beauty to the ornamentation by providing shadows and highlights that give depth and character. It can apply to other metals. |
| Oxide |
A compound containing one oxygen atom per molecule. See also dioxide. |
| Oxidize |
The act of combining with oxygen to make an oxide. Oxidized metal is rusted. |
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