Andradite is a mineral species of the garnet group. It is a nesosilicate, with formula Ca 3 Fe 2 Si 3 O 12. Andradite includes three varieties: Demantoid: Vivid green in color, one of the most valuable and rare stones in the gemological world. [7] Melanite: Black in color due to limited substitution of titanium for iron.

Andradite is a member of the Garnet group, and although not as well-known as other Garnets such as Almandine or Pyrope, it is still fairly abundant and can produce fine Garnet gemstones. A valuable gem form of Andradite is the rare Demantoid, which is a transparent green variety that is highly lustrous with an adamantine luster.

Demantoid garnet, the chromium-bearing, green variety of andradite, is the most well-known and valuable andradite. For more information on value and quality factors for this gem, consult our demantoid buying guide .

A red-brown, golden brown, or yellow-brown variety of Mn-bearing andradite. Rainbow Garnet: A trade name for a variety of andradite showing a distinct iridescence in rainbow colours. The iridescence is caused by the interference of white light with an overgrowth built of very thin lamellae, oriented parallel to {110} or other crystal faces. The...

Demantoid is the green gemstone variety of the mineral andradite, a member of the garnet group of minerals. Andradite is a calcium - and iron -rich garnet. The chemical formula is Ca 3 Fe 2 (SiO 4 ) 3 with chromium substitution as the cause of the demantoid green color.

2024年7月1日 · Andradite is a garnet mineral species that encompasses several distinct varieties, each with its own unique characteristics. The most well-known types of andradite include: Demantoid: Demantoid is one of the most famous and valuable varieties of andradite due to its brilliant green color and high dispersion, which gives it a fiery appearance.

Andradite garnet, a member of the garnet group, is a calcium-iron silicate mineral characterized by its chemical formula Ca3Fe2(SiO4)3. It possesses a cubic crystal structure and is part of a family of related minerals that share similar arrangements of atoms.

2023年5月1日 · Discover andradite, a prized garnet known for its stunning hues and dazzling brilliance. Learn about its properties, pricing, formation, and more in our guide.

Andradite is the most is the most lustrous of the Garnets and has several gemstone varieties. The term Garnet describes a group name for several closely related minerals that form important gemstones, and Andradite is an individual member mineral of the Garnet group.

Andradiie, the rares t of the five well- known gem garnet species, is examined and characterized with respect to refrac- tiveindex, specificgravity, absorption spec- trum, color, and chemical composition.