Gemstone Focus: Quartz

Quartz,_Tibet

Rock Crystal (image source: Wikipedia)

Quartz is the generic name for stones with a basis of Silicon Dioxide and it covers a broad range of well-known semi-precious stones, including Amethyst and Citrine. It comes in a variety of colours, but the most common and widely available form of quartz is Rock Crystal (pictured above) which is colourless and transparent. It can be found worldwide but as with so many gems, some of the most important sources are to be found in Brazil.

The word itself originates from the Greek word krustallos which means ice, as originally Quartz was thought to be ice formed by the gods, and for centuries rock crystal has been used to make crystal balls – which can allegedly be used to predict the future. More modern applications include lenses and lamps, as well as the manufacture of glass.

Smokey and Rose Quartz are two more popular types of Quartz which are commonly found carved into objects as well as cut into stones, often en cabochon. At only 7 on Mohs Scale of Hardness, faceting on Quartz can be prone to wear over time so this should be taken into consideration when choosing your stone, along with the application for which it’s intended.

Rose Quartz in particular is hugely popular due to its delicate pink/peach colour, which makes it ideal for romantically themed carved flowers and beads. It tends to be cloudy rather than transparent in appearance so is rarely facetted, and the colour saturation is often greater on larger pieces, another reason why it is popular for carved objects.

67SPQR01_12

Rose Quartz Semi Precious Round Beads 4mm (67SP QR01)

Rose Quartz is also enjoying a boost in popularity this year due to its prime positioning as one of the colours of the year along with a pale blue shade. This has propelled the stone into the limelight, thus creating more demand.

Along with Amethyst, Citrine is perhaps the most suitable form of Quartz for facetted stones. It is beautifully transparent and golden in colour due to the presence of iron in its formation, and sits well in both silver and gold. However, unfortunately Citrine is rarely naturally formed, and its distinctive yellow colour is usually created by heat treating Amethyst until it changes hue. A fabulous by-product of this process is called Ametrine, a crystal which is part Amethyst and part Citrine and I have to say I am a big fan of these!

Ametrine_cut

Ametrine (image source: Wikipedia)

Quartz can also display a fibrous structure which changes the appearance of the stone yet again. Inclusions of crocidolite (blue asbestos) cause a chatoyancy effect which is otherwise known as ‘cats-eye’ and this manifests itself as either Tiger’s Eye which is black with yellow and brown stripes, or the less common Hawk’s Eye which is blue-grey or blue-green.

As if this wasn’t enough variation, Quartz will change in appearance yet again when it has mineral inclusions suspended within it, and the most common of these is known as Rutilated Quartz, Sagenite or Venus-Hair Stone. It is generally clear in colour, and contains needle like inclusions of rutile crystals which can be red, black or yellow. They have a metallic lustre and look spectacular as the light catches them. Inclusions in Quartz are not only limited to rutile crystals thought – black Tourmaline needles, gold, silver and pyrites are also commonly found with beautifully varied effects.

I think it is clear that Quartz is a fabulously diverse stone with much to offer. Its worldwide abundance means that prices are low, so it’s perfect for experimentation with minimal financial risk.

Quartz has multiple uses in the jeweller’s workshop so is well suited to many jewellery design ideas. Browse the full range of Quartz Gemstones and Semi-Precious Beads at Cooksongold now and add this versatile stone to your next piece.

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