Properties
Mineral group: Quartz
Chemistry: SiO2
Color: Colourless white, yellow, brown, pink, violet, green and others
Crystal system: Trigonal
Mohs Scale hardness: 7
Refractive index: 1,544-1,553
Birefringence: +0,009
Specific gravity: 2,63-2,65
Chemistry: SiO2
Color: Colourless white, yellow, brown, pink, violet, green and others
Crystal system: Trigonal
Mohs Scale hardness: 7
Refractive index: 1,544-1,553
Birefringence: +0,009
Specific gravity: 2,63-2,65
Information
May be confused with
Such a wide group can be confused with most other gemstones. In this "gemstone information" we describe a few, such as the common and the popular Amethist, Citrine and a few others.
Important in respect to confusion, what color, clarity, and features stone has.
Instruments for identification
- A good and important tool, particularly for the crystalline quartz , is the Polariscope with the Conoscope. These quartz' belong to the triagonal crystalline system and are anisotropic. This can be seen with the is the Polariscope.
- With Conoscope can do a diagnostic test for these quartz'.
- Of course you use a refractometer to determine the refractive index, which should be between 1.544 to 1.553 for crystalline varieties.
- Density is measured by hydrostatic weighing.
- Any inclusions can be viewed with the microscope, as well as, and this is very important, any color changes and / or color zoning. It is often the only way to distinguish synthetic quartz' (as it is very ample) from natural quartz. The synthetic are usually very uniform in color.
Known deposits
Quartz, which is one of the most abundant minerals, consequently is found in many places. Certain unusual or particularly qualitative variants may have few localities.
Treatments
Heat treatment is very common for quartz' varieties. Irradiation and Diffusion are also used. As previously mentioned, there are a plethora of synthetically made quartz, which also causes
major problems in the trade with natural gemstone material. Glass, in various colours, are common simulants.
Miscellaneous
Quartz is a mineral in a broad sense with similar chemical composition. Quartz can be divided into two main subsets. Crystalline (macro-crystalline), the variety is generally associated with quartz. This group includes Quartz, Amethyst, Smoky Quartz, Cat's eye Quartz others.
The second group are polycrystalline (micro-crystalline), and have in turn several subgroups. Here we find the groups Chalcedony, Jasper, Quartzites and silicate replacements. Known examples here are Agate, Carnelian and different varieties of jasper and Tiger’s eye. There are also other Quartz which consist of the Opal Group.
Read/learn more about Quartz by klick link on respective kind (klick return button in your browser when you want to go back to Riddgem).
Varieties/Types
Amethyst - A purple variety of Quartz.
Ametrine - A mixture of Amethyst and Citrine in the same crystal.
Aqua Aura - Clear quartz artificially coated with thin layer of metal to turn it iridescent.
Chalcedony - A cryptocrystalline variety of Quartz.
Agate - A banded variety of Chalcedony.
Iris Agate - An iridescent variety of Agate.
Onyx - A monochromatic Agate with black and white banding.
Sardonyx - A monochromatic Agate with red/brown and either black or white banding.
Binghamite - Chatoyant Chalcedony with fibres of hematite/goethite.
Bloodstone - A dark green/greenish-blue Chalcedony with small red blood-like spots.
Carnelian - A red to orange variety of Chalcedony.
Chrome-Chalcedony - Emerald green Chalcedony, colored by chromium.
Chrysoprase - A green Chalcedony coloured by inclusions of Ni minerals.
Dendritic Agate - A chalcedony containing contrasting branching, or dendritic, mineral inclusions.
Moss Agate - A translucent chalcedony containing green strands of chlorite.
Fire Agate - A variety of Agate containing iridescent spheroids of limonite.
Jasper - Jasper is a dense, opaque, microcrystalline variety of Chalcedony.
Dallasite - A variety of Jasper from Vancouver Island, British Columbia, Canada.
Orbicular Jasper - Jasper containing numerous spherical inclusions.
Petrified Wood - A decorative type of fossil wood where the original organic material has been replaced - usually by chalcedony, agate, opal, etc.
Pietersite - Chalcedony with embedded fibers of amphibole minerals, causing chatoyancy.
Sard - A brown to brownish-red translucent variety of Chalcedony.
Citrine - A yellow to yellow-orange or yellow-green variety of Quartz.
Iris Quartz - A quartz showing rainbow colours.
Mystic Quartz - Clear cut quartz coated with thin layer of titanium on pavilion.
Prase - Prase is a leek-green variety of Quartz.
Prasiolite - A green variety of Quartz.
Rock Crystal - A transparent colourless variety of Quartz.
Rose Quartz - Pink variety of Quartz.
Rutilated Quartz - A clear Quartz shot through with golden needles of rutile.
Smoky Quartz - Smoky-grey, brown to black variety of Quartz.
Morion - Sometimes synonymous with Smoky quartz, but often reserved for nearly black Smoky quartz.
Tiger's Eye - Chatoyant yellowish-brown variety of Quartz.
Falcon's Eye - Trade name for a blue variety of Tiger's Eye.
Gemstone Guides & Knowledge
Read more about Quartz on RIDDGEM Blog
Watch movies and Shorts about Quartz on RIDDGEM YouTube
Quartz in Healing
In crystal healing, quartz is considered one of the most powerful and versatile crystals.
Read/Learn more about Quartz - Healing Properties
