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General jewelry information, Glossary

We bring here general jewelry related information, which answers some of the questions frequently raised by our customers. We would appreciate any comments and requests for further information.

Karat (Gold)

Measuring unit describing the purity level of gold. Based on a 24-level scale, where 24 Karat gold means pure gold or 99.9% gold. Similarly, 14 Karat gold would be an alloy in which 14 parts out of 24 are pure gold and the remaining 10 parts are other metals, which determine the color and mechanical properties of the gold alloy.

Commonly used Gold purities

Gold, in its pure (24K) form, is a very soft metal. In general, this softness makes it unsuitable for jewelry work unless the gold is supported by a substrate, is thick enough, or when the softness is a desired property e.g. for stone wrapping. To achieve the mechanical strength required for common jewelry work, other metals are added to the gold to form a gold alloy. In Israel and Europe, 9 Karat (37.5% gold) is the lowest gold purity that could be sold as gold. 10K (41.7%) is the lowest gold purity sold as gold in the USA. Other popular gold purities used worldwide are 14K (58.3%), 18K (75%), 21K (87.5%), 22K (91.7%) and 24K (99.9%). Gold alloys become softer and brighter as the gold concentration (Karat) increases.

Colors of Gold

The metal added to gold to make an alloy is varied to control the color and mechanical properties of the alloy. Frequently added metals are Silver, Copper, Palladium, Nickel and seldom small quantities of Aluminum, Zinc, Iron or Manganese. The most common colors of gold are yellow, red and white. Rarely used are the green, purple and blue gold, some of which are obtained by creating a special oxide surface layer. For further reading visit the World gold association.

Yellow Gold

The natural color of gold is bright yellow. The base system used for making yellow gold lower than 24K is Gold-Silver-Copper. Different ratios of Silver and Copper are used to determine the color tendency towards red or greenish. For example, one of the common European standards for 18K yellow gold is 75% gold and equal shares of Silver and Copper, 12.5% each. Top

Red Gold

A gold alloy with high Copper content. The higher the Copper concentration, the more red the gold alloy becomes. Top

White Gold

When metals with typical white brightness are added to gold, the result is an alloy with a white color tendency. Base system compositions used for obtaining white gold are the Gold-Palladium-Silver and the Gold-Copper-Nickel-Zinc systems. Nickel is a metal capable of penetrating the blood circulation through the skin and causing severe allergic symptoms. If you are allergic to Nickel and decide on wearing white-gold jewelry, it is highly recommended that you verify that the white gold is Nickel-free. Top

"Gold plated"

A term often used for a base metal plated with a fine layer of Gold. The plating layer is typically very thin with a thickness of several tens of microns (1 micron = 0.001 millimeter). When purchasing gold-plated jewelry, one has to take into account that the gold layer might be scratched or wear off with time. Top

Gold Filled

The name speaks for itself: Gold filled is gold, filled with base metal. The result material is base metal in the metal interior and gold on the exterior. In contrast to gold plating, the gold in gold filled metal is a substantial part of the metal, typically 5%. This is a relatively thick gold layer that wouldn't scratch or get off under normal use and care of gold filled jewelry. We use 14K Gold filled, namely 14K Gold forming the external 5% of the metal. Gold filled jewelry is an excellent solution for those of us who like the look of Gold but not its price.
For a great resource describing the manufacturing processes of gold filled we recommend the following article at artisanplating.com
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Sterling Silver

Sterling Silver, or 925 Silver is the standard used in the jewelry industry. Since pure Silver is too soft for standard jewelry work, Copper is added to the Silver alloy to generate the required mechanical strength. Sterling Silver alloy contains 92.5% Silver and 7.5% Copper. Top

999 Silver

999 Silver, or fine Silver, is pure Silver or more accurately 99.9% Silver. It is a very soft Silver metal used generally in wire jewelry and stone wrapping. Top

Jewelry stamping, hallmarks

By law, jewelry items have to be marked with a metal purity hallmark and a trademark of the manufacturer/artist. Jewelry weighing below 2 gram do not require marking. Usually, hallmarks are found on the back side of the jewelry or near the clasps. Often, the marks are very small in size and require the use of a magnifying glass in order to observe their detail.

When a composition of metals is used in jewelry, the mark would correspond to the lowest value metal used. For example, 925 mark will appear on an item composed of both 14K Gold and Sterling Silver, 14K mark will appear on an item containing both 14K and 24K Gold, etc. The description of the item may, of course, include all types of metals and composites used for crafting the item.

Below is a list of hallmarks commonly used for marking jewelry:

Carat (Gemstones)

A unit of weight, commonly used for weighting precious and semi-precious stones. One Carat equals a fifth of a gram (1 Ct. = 0.2 gr). For each stone and a known cut, a conversion table can be made to convert between the Carat value of the stone and its size. Therefore, the Carat value of a stone is often used as a sizing measure, especially for diamonds. Ct. is the common abbreviation for Carat.
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Points (Gemstones)

The Carat is further divided into smaller weighting units named "points". 100 points equal 1 Ct. (1 point = 0.002 gr).
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Gemstone cuts

Gemstones are polished in several standards cuts. We describe here some of the common gemstone cuts.

Cabochon - Dome shape polished gemstone. One side of the stone is flat and the other is in dome shape.	Round Amethyst cabochons
Rose Cut - The stone is cut in way that its bottom is flat and the top is faceted.	Round faceted Smoky Quartz gemstone
Emerald cut / Octagon cut - Square or rectangle shaped stones with truncated corners. Facets run in steps parallel to the gemstone circumference.	Left to right: Iolite, Emerald and Ruby, emerald-cut gemstones
Faceted - Gemstone cut in a way to include many facets. The multiple facets structure increases light reflection and gives the stone a bright and shining look.	Faceted oval Citrine gemstones Faceted Crystal and Blue Goldstone beads
Brilliant cut / Diamond cut - The most famous faceted cut used for round gemstones. The stone is cut with 58 facets in a special geometry for very high light reflection. The incident light enters the stone through the flat top surface, circulates within the stone and reflected back from the top surface. Commonly used for diamonds.	Brilliant cut Blue Topaz and Iolite gemstones
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