Black Tourmaline Gemstone 4.21ct
This Tourmaline is natural gemstone which is black colour, it’s Originates from India and it’s exact weight is 4.21ct the measurements are 12.27×10.60×4.07mm, the shape and cut of this stone is Oval mixed cut. It’s graded Transparent and clarity is Excellent. This 4.21ct black natural Tourmaline Gem is available for ready to ship anywhere in the world. You can also select Certification and shipment method as optional.
|Shape/cut||Oval Mixed Cut|
Tourmaline Gemstone 4.21ct
Properties Of Tourmaline
Chemical Composition: Na(Al; Li)3Al6(BO3)3Si6O18(OH)4
Hardness: 7.0 – 7.5
Specific Gravity (Density) : 3.06 – 3.08
Refractive Index: 1.623 – 1.657
About Tourmaline Gemstone
A tourmaline is a group of related minerals, all having the same basic crystal structure but varying widely in chemical composition and colour. The name Tourmaline is from the Singhalese word tourmaline, meaning mixed coloured stones because Tourmaline is found in so many different colors it was often confused with other gem types.
The four most common and well-known varieties of Tourmaline are Elbaite, School, Dravite, and Uvite and can be distinguished by their colours and transparencies. Most gem Tourmalines are the variety Elbaite.
Elbaite is the most colourful of all gems and is available in almost all the colors of the spectrum. The most well known Elbaite gems are Achroite (colorless), bi-color (usually pink or red and green, also blue and green), Indicolite (blue), Orange, Paraiba (containing copper), Rubellite (pink to red), Siberite (lavender), Verdelite (green), Watermelon (green and pink or red) and yellow.
Schorl is the iron rich Tourmaline that is black and opaque. Although not that popular as a gem, it is the most common of the Tourmalines in nature and is a common accessory mineral in igneous and metamorphic rocks. Even though it is opaque and black, it can be faceted into beautiful gems and was very popular in mourning jewellery during the Victorian era. It is currently regaining popularity. Schorl is also found as the black needle-like inclusions in Quartz, known as Tourmalinated Quartz.
The two other well-known Tourmalines are Dravite and Uvite. Both are magnesium/iron rich members of the Tourmaline group. Although not nearly as well known as the many colours of Elbaite, Dravite and Uvite are becoming better known and are being collected as mineral specimens and gemstones. Dravite is usually light to dark brown, black or may also be colorless. Uvite is usually found in dark colours such green, yellowish brown, brown, red and black