Definitions [A-D]

About The Dictionary

Our Dictionary has been devised to provide you with fundamental knowledge of the materials and the production techniques we utilize to create our products. Additionally, we have clarified some of the general terms we use throughout the site.

We’d love to hear from you regarding any additions or improvements you may have for us.

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Abalone, a type of Mother of Pearl, is also known as the 'Paua Shell'. For centuries the Maori tribes of New Zealand have used Abalone for mystical carvings and jewellery. This Mollusks shell has been referred to as 'Sea Opal' because of its colourful resemblance to the Opal.

A type of thermoplastic that comes in many colours and various levels of transparency.

No stone is more creatively striped by nature than Agate. It is a very common stone often used in jewellery. It's found in a wide range of colours including black, grey, brown, yellow, pink and blue. Agate is a porous stone and can be dyed to enhance the colour. In ancient times the stone is said to have had the power to quench the thirst and protect against fever. The mining of agate was documented as early as the 1490's in Germany; the stone is also mined in South America. Agate has a Mohs hardnessrating of 7.

The Alexandrite is a mineral that changes colour dependant on whether it is viewed in natural or artificial light. Alexandrite can appear red in candle light and blue/green when in fluorescent light. The stone was first discovered in 1834. The largest stones are mined mainly in Burma and Rhodesia and can weigh up to 30 carats (6.0g). However the higher quality stones are found in the Ural Mountains, Russia. Alexandrite has a Mohs hardnessrating of 8.5.

Amber is an ancient and valuable stone which is sourced from fossilized tree resin, (conifer/pine trees). It is also a natural hydrocarbon that comes in many colours ranging from yellow to brown to blue. In the past, it was thought that Amber possessed magical powers and protected the wearer from evil. Due to the nature of the source amber can sometimes contain small insects. The two main sources of Amber today are The Baltic's and the Dominican republic. Amber has a Mohs hardnessscale rating of 2.5.

Amethyst is the most striking member of the crystal quartz family. It's usually purple in colour, however crystals have been know to have a colour range of milky white to a very pale lavender. The ancient Greeks believed it to have the power to make the wearer immune to the affects of alcohol. Large deposits of the stone have been found in Brazil and neighbouring Uruguay. Another major source is Madagascar. Other countries known for having deposits of the stone are Canada, Tibet and Sri Lanka. Amethyst has a Mohs hardnessrating of 7.

Apatite is a clear to opaque stone that comes in many colours including violet, blue, yellow and green. This stone is rarely used in jewellery because it is too brittle and soft. The major sources of Apatite are Brazil, Burma and Mexico. Other known sources are Germany, India, Norway and Spain. Apatite has a Mohs hardnessrating of 5.

This is the effect of light rays forming a star on the surface of certain types of stones. Asterism is created by the reflection of light from thin, fibrous or needle-like occlusion of the gemstone. Sapphire and Ruby Cabochanscan show effective six-rayed stars while some other gems can produce 4-rayed stars. 12 rayed-stars are very rare.

Aquamarine got its name from its seawater-like colour which, in Latin, translates to 'Water of the Sea'. Aquamarine is a cousin of the Emerald, as they both belong to the Beryl family of stones. This beautiful stone can be found in many countries: Australia, Burma, China, and Zimbabwe to name a few. The largest Aquamarine stone has been found in Brazil weighing over 100kgs. The Mohs hardnessrating for Aquamarine is 7.5-8

Aventurine can also be referred to as 'goldstone' and it is part of the quartz family. In its most common form, Aventurine is green. However it can be orange, blue, yellow or even grey. The stone has high mineral content and can have a glistening effect. Aventurine has a Mohs hardness ratingof 6.5

Azurite Malachite
Azurite is a copper based mineral that is often used in jewellery. Its colour ranges from very dark green to very light blue. There are many sources of the stone and it can be found in the USA, Southwest Australia, Zambia, Morocco and Mexico. The Mohs hardness rating for the stone is 3.7- 3.9
A bail is a metal component that usually attaches the pendant to a chain or cord.

Base metals are non-precious metals that will corrode or oxidise very easily. Copper, zinc, tin and lead are the main base metals used in the production of jewellery.

Beads are small objects, usually made from glass, stone, wood, plastic, seeds, or ceramic. Each bead has a hole on either end to pass the string/cord through in order to make a necklace or bracelet.

The Beryl family comprises several stones (Aquamarine, Emerald and Morganite) that each have their own unique colour yet share the same properties. These typical hexagon beryl crystals are mainly found in gemstone deposits in South America and Western Africa. They also occur in Russia, Ukraine and the USA. The Mohs hardnessrating for beryl is 7.5-8.

The Modern Birthstone chart is the official birthstone list from the American National Association of Jewelers, Jewelers of America, adopted officially in 1912. In October 2002, this list was updated to include Tanzanitefor December's birthstone by the American Gem Trade Assoc. (AGTA).
January - Garnet
February - Amethyst
March - Aquamarine
April - Diamond
May - Emerald
June - Alexandrite
July - Ruby
August - Peridot
September - Sapphire
October - Opal
November - Topaz or Citrine
December - Turquoise Tanzanite, or Blue Zircon

Bloodstone is an opaque Chalcedony with red spots. The spots in the stone are caused by iron oxide. An old name for bloodstone that is still used in parts of Europe is 'Heliotrope'. It is mainly used for ornamental objects. The most notable deposits are in India while other known sources are Australia, Brazil, China and the USA. Bloodstone has a Mohs hardnessrate of 6.5 to 7
Cabochon describes a gemstone that has been domed and highly polished as opposed to faceted. Cutting and polishing in this way is usually applied to opaque stones, while faceting a gem would normally apply to a transparent stone. The softness of the stone has to be taken into account as any stone with Mohs hardnessRating of less than 7 is too soft to be formed as a cabochon because it will scratch too easily.

Cameo is a method of carving a gemstone or shell, where the design is raised above a background of a different colour. The 3 materials that are usually used in this process are shell, glass and Agate.

Carat is the standard measure of weight used for gemstones. One carat is equivalant to 0.2 gram and a hundredth of a carat is called a 'point'. This unit of weight was introduced in 1907.

Carnelian, also known as cornelian or carneole, is probably named after the Kornel Cherry because of its brownish red-orange colour. Carnelian can be translucent to opaque. The highest quality Carnelian is sourced in India, Brazil and Uruguay. Carnelian has a Mohs hardnessrating of 7.

Chalcedony is a family of minerals (cryptocrystalline quartz) that are often milky to greyish to blue. This large family of stones includes: Agate, Onyx, Carnelian, Bloodstone and Jasper - to name a few. Chalcedony is a porous and translucent stone that has a Mohs hardnessrating of between 6 and 7.

A choker is a type of necklace that fits tightly around the neck. Chokers vary in size with standard lengths between 14" and 16".

Chryscolla (meaning 'golden lime' in Greek) has an aesthetic blue/green colour. This mineral has been used in ornaments for years and years however it was only classified as a mineral in 1968. It forms in the oxidised zones of copper found in the earth's crust. Notable deposits have been found in the USA, Russia, Chile and the Congo. Chryscolla Mohs hardnessrating varies from 2-4.

An apple green coloured gemstone from the Chalcedony family. The best known sources of Chrysoprase are Queensland, Western Australia, Germany, Poland, Russia, Arizona, California, and Brazil. Chrysoprase has a Mohs hardnessrating is 6-7.

Coral, also know as Precious coral, is an organic gemstone. The distinguishing features of precious coral are its durability and intensely coloured skeleton . The coral typically grows on rocky sea beds at depths of between 10-300m in areas around Japan, Taiwan and near the straights of Gibralter. Coral has a Mohs hardnessrating of 3.5

Corundum is named by its colour. Red corundum is called 'Ruby' and blue corundum is called 'Sapphire'. In its most rare and pure form, Corundum is colourless and called 'White Sapphire'. The mining of the stone takes place in different parts of the world depending upon its final use. Corundum is mined in many countries around the world including Thailand, Sri Lanka and Australia. Corundum is a very hard mineral with a Mohs hardness rating of 9, only Diamondsare harder.

Crystal is high quality glass containing at least 10% lead oxide. Lead is added to the melting process to produce a very clear glass that resembles Rock Crystal. The process of making lead crystal was discovered by the English glassmaker George Ravenscroft in 1676. Crystal is coloured by adding various metal oxides during the melting process.

Cultured Pearl
Long ago pearls were seen as a financial investment alongside property and artwork. They were so rare because they were created by chance in the sea. Today, however, Pearls are created artificially by placing shell beads into the oyster which is then placed back in the sea for several years. Most of the cultured pearls today are created in Japan in the warm waters of the South Pacific. Tahitian Black pearls are created from larger oysters and freshwater pearls are created inside mussels from China. This method of creating pearls was invented in 1893 by Kokichi Mikimoto. Pearls have a Mohs hardnessrating of 3.

Cubic Zirconia
A very inexpensive stone that is created in laboratories and used as a cheaper alternative to Diamonds. They were first developed back in 1977. When created, the stone is usually optically flawless with no colours. However, colours can be added during the forming process with chemicals. The Mohs hardnessrating for CZ is 8.

There are three types of cuts that can be applied to gemstones, The Faceted, The Plain and the Mixed Cut.
The FacetedCut is applied mostly to transparent Gemstones.
The Plain Cut, know also as Cabochan (no facets) where the surface is smooth and even with a very high polish. This type of cut is used on Opaquegemstones.
The Mixed cut is a combination of the previous two cuts, the upper part of the gemstone will be facetedand the lower part of the stone will be smooth or vice versa.
Diamonds get their name from the Greek word 'adamas' which translates to 'The Unconquerable'. Diamonds are very precious and optically very beautiful. Due to its visual beauty and hardness the Diamond is regarded as the 'King of Gemstones'.
Diamonds are formed from carbon (basically coal) that crystallises under immense pressure over a very long period of time. Until the 1800's, diamonds were only found washed out of diamondiferous places (volcanic pipes that release the Diamond bearing rock out into the earth's natural environment).
The most famous pipe in South Africa is the Kimberly Mine where mining was discontinued in 1914. Today, Australia leads the way in Diamond production closely followed by China and Russia.
There are a number of famous Diamonds which have been defined by their size and beauty, to name a few:
The Dresden was a green diamond from India which weighed 41 carats.
The Star of Africa weighed a massive 530.20 carats and was cut from the largest rough diamond ever found; it weighed in at 3106 carats. This stone is now kept in the Tower of London.
A Diamond's value is decided by the four C's: Carat, Clarity, Colour and Cut. Diamonds are found in many colours - mostly a yellowish colour until given various treatments. The rare colours are green, red, blue, and purple. These are known as 'fancy colours'. These stones are very valuable and have been known to fetch collector's prices. The inner perfection of a diamond is measured by Clarity. Polished diamonds without any occlusions under 10X magnification are considered flawless.
There are many types of cuts for Diamonds both new and old with The Brilliant Cut and The Princess Cut to be the most common. Some older cuts are the Point Cut, the Old European Cut, and the Peruzzi Cut. Carat is the unit of weight that is used to weigh the stone. Diamonds are the hardest gemstone on the Mohs hardnesswith a score of 10.

Diopside comes in two varieties: Black Star and Chrome. Diopside has several drawbacks in that it's only available in small sizes and when the stone does come in larger size the colour is too deep and dark. Major sources are found in Siberia, Yakutia, Canada and South Africa. Diopside has a Mohs hardnessrating of 5.5 û 6.5.