Amethyst

Amethyst is a gemstone from quartz family. Amethyst was and remains one of the most popular stones; it was used in many ornaments XIX – XX centuries. Russian stone was always considered as the best because at artificial light it had the reddish shade. However, amethyst can have the diversified shades from light-lavender to violet (the Siberian amethyst) in which there are the splashes of the purple colour at a cutting. The name “Siberian” is used for the description of any stone with a rich violet colour. The stone of the deep homogeneous violet colour is more expensive, than faintly-lavender.

It is possible to find crystals of ametrine which are often amethyst, and partially – citrine, and often contain many inclusions, changing the colour. Besides, amethyst is a little dichroic, i.e. its colour has either a bluish shade, or reddish, depending on a sight corner.

Deposits of amethyst: Russia (Urals Mountains) and the deposits are also found in Namibia and Zambia.

Citrine (yellow quartz) is a gem from quartz family. As well as smoky quartz, citrine often receives confusing name of topaz or quartz topaz. Citrine is a cheap and very widespread stone, in difference from precious topaz, it can also reach big sizes.

The stones have from gentle-lemon, yellow to deep and reddish-brown, amber colours. The usual natural colour is pale golden. However, natural dark citrines are also met. There aren’t many dark citrines; the darker colour is- the more expensive stone is. At heat treatment of pale amethyst or smoky quartz it is possible to receive citrine of the lemon-lime shade. Citrines from Madeira and Palmera are the most valuable transparent stones as they are natural and extracted in the limited quantities.

Deposits of citrines: Russia, Africa, Australia, Brazil, Japan, Myanmar (Burma), Spain.

Smoky quarts

Smoky quartz (rauhtopaz) is a gem from quartz family. Unfortunately, smoky quartz is often ignored, and the potential of this stone is not estimated up to the end. The spectrum of the soft, gentle colours of the stone is rather wide: from gentle greenish-brown, rich chocolate to dark brown, colours of charcoal and almost black. Sometimes this stone is named after the names of the areas in Scotland, Cairngorm and Marion where the extraction of smoky quartz is. Natural smoky quartz is extracted in great volumes and in big sizes. Smoky quartz is very beautifully in the frame from white metal.

Deposits of rauhtopazes: Russia Africa, Australia, Brazil, Japan, Myanmar (Burma), Spain

The specification of quartz

Hardness 7 on Moos scale

Density 2,65

Factor of refraction from 1,544 to 1,553

Crystal lattice: quart forms a single crystal in the trigonal system; habitus of the crystal is rods with 6-angles pyramidal ends. The surfaces of the crystals often have horizontal marks.