Topaz

Topaz is an aluminum silicate that contains fluorine and hydroxyl. In its pure form it is colorless (white). Impurities are what cause variations in color. Topaz has a history that goes back at least two thousand years. The use of topaz goes back to Egyptian times when the ancient Egyptians believed that yellow topaz received its golden hue from the Sun God, Ra. Some believe that “topaz” is a Middle English word, which was acquired from the Old French word “Topace” and Latin “Topazus”, the root of which is in the Greek word “Topazios” or “Topazion”; the ancient name of an island in The Red Sea where the ancient Greeks mined a yellow gem that they believed to be topaz. The name of the island means “to seek” in Greek. It could have been so named because it was difficult to find amongst the mist. This island is now known as “Zabargad” or “St John’s Island”, and it is thought that the gem mined by the ancient Greeks was actually “chrysolite”. The Christian Old Testament makes references to topaz, but this gemstone may have also been “chrysolite”, rather than topaz. The word “topaz” could also have stemmed from the Sanskrit (the ancient language of India) word, “tapas”, which means “fire”.

Topaz can be distinguished from diamond, ruby, sapphire, citrine, apatite, brazilianite, zircon, fluorite, kunzite, tourmaline and orthoclase by its hardness (8 on the Mohs scale). It can be told apart from aquamarine by its orthorhombic crystal structure. Phenakite can be distinguished from topaz by its trigonal crystal structure. Spinel can be identified from topaz by its cubic crystal structure. Topaz has a lower density and different chemical composition than chrysoberyl, and chrysoberyl usually has no fluorescence, whereas topaz has some weak fluorescence, which can help to distinguish between the two. Precious beryl can be mistaken for topaz, but has indistinct cleavage, whereas topaz displays perfect cleavage. A lot of other less valuable gems are misleadingly sold as “topaz”, such as Madeira topaz, occidental topaz, Palmeira topaz, Rio topaz, saffranite topaz, Scottish topaz, smoky topaz and Spanish topaz. However, in most cases, these gems are citrine quartz, with the exception of smoky topaz, which is smoky quartz. Indian topaz, king topaz and star topaz are all actually sapphire.

Topaz Color

Topaz ranges from colorless (white) to yellow, orange, red-brown, light to dark-blue, pink to red, violet and light-green. This is the reason why it can be mistaken for many other gemstones. Naturally colored topaz gets its color from iron and chromium; the impurities cause color, whereas pure topaz is colorless. Most unadulterated topaz is colorless or pale blue. The most rare and valuable topaz is yellow, or pink to reddish-orange, and is known as “imperial topaz” or “precious topaz”. Some yellowish-brown topaz gems can gradually fade when continually exposed to daylight. Red and violet topaz is incredibly rare. A lot of topaz is treated in order to enhance the color. Reputable gem sellers declare any enhancements.

Topaz Clarity and Luster

Topaz is transparent to translucent. It exhibits high clarity with few inclusions, so topaz gemstones can be examined by the naked eye and found to be “eye clean”, which means that no imperfections can be seen. Topaz is highly prized for its brilliance and vitreous (glassy) luster.

Topaz Cut and Shape

Topaz is a very versatile material. Therefore it can be cut into a great variety of shapes, such as square, round, octagon, pear, oval, heart and even fancy shapes such as fish or birds. Strongly colored gemstones are usually scissor cut whereas weakly colored stones are generally brilliantly cut. The facets show off the clarity and brilliance of the gem. When topaz has irregular inclusions, it is often cabochon cut. Its hardness makes it resistant to scratches. However, lapidarists must handle topaz carefully, due to its perfect cleavage, which means that it can easily fracture.

Famous Topaz Gemstones

The ancient Greeks believed that topaz was a powerful stone that could increase the strength of the wearer and even provide invisibility in desperate times. Both the ancient Egyptians and the Romans associated topaz with the Sun God.

The “El-Dorado Topaz” is the largest faceted gemstone in the world and weighs an enormous 31,000 carats (6.2 kg). It is an emerald-cut yellow topaz gemstone that was found in Minas Gerais, Brazil and then weighed 37 kg, uncut. The American Golden Topaz, which is another enormous gem, weighs an astounding 22,892.5 carats (4.6 kg). It is on display in the Smithsonian National Museum of Natural History in Washington D.C. It is one of the largest faceted gems in the world, came from Minas Gerais in Brazil and two years were taken to cut its 172 facets. There are unbelievably enormous uncut yellow topaz crystals reaching a mass of 31 kg (the Lindsay Uncut Topaz) and 50 kg (the Freeman Uncut Topaz). These uncut gems are on display as part of the Smithsonian Museum’s collection. The Chalmers Topaz is another huge cut topaz, and weighs 5,899.5 carats (1.17990 kg). It is white with a blue cast and is a brilliant-cut oval-shaped gem. It is displayed at the Field Museum of Natural History, USA. In 1964, some blocks of blue topaz, each weighing an amazing 100 kg were found in the Ukraine. Another famous topaz gemstone is the 1640 carat Braganza “Diamond”, which is part of the Portuguese Crown Jewel collection. It was originally believed to be a diamond, probably because it was found in Minas Gerais, near where diamonds had been discovered, but was later found to be a white topaz crystal.

Source: Gem Select