Andradite
Gemological information for andradite
Color
Green: demantoid, Black: melanite, Yellow: topazolite ...
Andradite
Overview: Andradite is a rare Garnet, and its gem varieties are highly regarded. It is a Silicate of calcium and iron. The most valuable gem form of Garnet is the rare Demantoid variety of Andradite.
Andradite
Andradite garnets are really quite rare, but have some outstanding qualities. The most spectacular garnet of all is the demantoid. Demantoid garnet is an intense medium green andradite.
Enhancements
Andradite grossular garnet is not enhanced.
More information on gemstone enhancements.
Andradite Grossular ...
Andradite: A garnet used as a gemstone of the grossular family consisting of calcium iron silicate and having any color ranging from yellow and green to brown and black.
Andradite
A variety of Garnet that is typically green but can also be black or yellow. Measures between 6.5 - 7.
Aquamarine ...
Andradite and Demantiod
With its beautiful green color, for many years the queen of the garnet family was the Demantoid garnet, which was discovered in Russia's Ural Mountains in 1868.
[edit] Andradite
Andradite (the black mineral)
Andradite is a calcium-iron garnet, Ca3Fe2(SiO4)3, is of variable composition and may be red, yellow, brown, green or black.
Andradite garnet furnishes brilliant green stones, which have been incorrectly named "Olivines" by the trade. The name is unfortunate as it is identical with the true name of the mineral which gives us peridot.
Andradite
Ca3Fe2(SiO4)3
In addition to the purer end members mixed garnets such as malaia (or malaya, a pyrope-spessartite) and grandite (a grossular-andradite mixture) exist. The purplish pyrope-almandine mixture is called rhodolite.
Andradite garnet is usually black and of no interest to the gem trade, but one variety called "Demantoid" is a lively green. It is a little on the softside and very brittle so it needs good protection in jewelry.
Andradite"Green crystals from central California.
Grossular"A greenish garnet illustrated by a well-formed crystal.
Pyrope"Wine-colored grains in a California eclogite.
Andradite is a calcium-iron garnet and may be red, yellow, brown, green or black. Green andradite (demantoid) has been called the ‘the emerald of the Ural’ and is one of the most prized of garnet varieties.
Andradite
Only important variety is Demantoid, a very rare, brilliant yellow-green andradite.
Has very high dispersion (0.057; higher than diamond) and high R.I.( 1.89); accounts for brilliance, also name (demant is Dutch for diamond).
Andradite is one of six gemstone species within the garnet group. It includes several gem varieties, the most notable of which is demantoid, a rare and highly prized green garnet.
andradite garnet, quartz (including Japan-law twins), pyrite
Finch Mine (Barking Spider Mine)
near Hayden, Az.
Mali (andradite &
grossular)
Grossular:
Ca3Al2Si3O12
Tsavorite (green), hessonite (orange) & other colors ...
andradite
Crystallography: Isometric
Colors : Demantoid is green, Topazolite is yellow, Leuco is colorless Hardness: 6.5
Specific gravity: 3.85
Refractive index: 1.89 ...
Some garnets used as gemstones include pyrope (the deep red garnet), almandine, spessartine, grossular, the iron-aluminum dark red garnet (also known as the carbuncle stone), Uvarovite (rare), and the lustrous Andradite (which includes the valuable ...
Demantoid: One of the rarest and most valuable varieties of andradite garnet. The color is generally a vibrant yellow-green. Demantoid garnets have brilliance akin to that of a diamond.
Not only do garnets have many colours; they also have many names: almandine, andradite, demantoid, grossularite, hessonite, pyrope, rhodolite, tsavorite, spessartine, and uvarovite, to quote but a few.
Almandite and almandite-pyrope solid solution garnets are the best abrasive types, but andradite, grossularite, and pyrope also are used.
All species of garnet have been used as gemstones.
d'Andrada who named the gem 'allochroite' in 1800, the Andradite garnets varies in many colors from black to shades of yellow and green. The lively green and rare demantoid garnet is the most valuable of all the garnets.
Melanite is a black titanium bearing variety of andradite and demantoid is a rich green variety. Malaya is a trade name for a pyrope-spessartite that varies in color from red, through shades of orange and brownish orange to peach and pink.
Andradite garnet is found in yellow, green, or brown. Chromium-rich emerald-green andradite, found in Russia in limited supply, is known as demantoid garnet.
Andradite garnets occur in green, yellow, orange and black. Spessartine are orange, while Almandine are purple, Pyrope-Almandine are purple red or purple pink and commonly known as rhodolite.
The green transparent variety of Andradite garnet
Diamond
The most cherished and among the most valued gemstones, a mineral composed essentially of carbon in the cubic or isometric crystal system; Most common in colorless to slightly yellow or brown, ...
Some Other Varieties are Andradite, Essonite, Tsavorite, Spessartite, Melanite, Allochroite, Ouvarovite and Demantoid. This stone has a long history of use as a medicine stone and was used for healing blood and lung diseases.
Iolite ...
Demantoid Demantoid is a rare and valuable andradite garnet. It exhibits a range of greens from dull to bright emerald green and on rare occasions displays yellow. On Mohs scale of hardness, demantoid is relatively soft at 6.5.
Named varieties of Garnet include Andradite, Tsavorite, Grossularite, Essonite, Pyrope, Almandine, Spessartite, Melanite, Allochroite, Ouvarovite, Demantoid, and Rhodolite.
Gaspetite ...
They are a rare variety of andradite. Demantoid garnets have characteristic inclusions that look like horsetails. Demantoid garnets have a hardness of 6-7 and a specific gravity of 3.8 - 3.9.
In fact garnet is a group of six closely related minerals: almandine, pyrope, grossular, spessartite, andradite, and uvarovite. In practice many garnets contain a mixture of two or more of these varieties.
Demantoid Garnet: A form of andradite they are rare, green, lustrous and valuable garnets that were popular in the 1800s.
Demilune: A stone shaped like a half-moon.
Demi-Parure: The term for two items of matching jewelry.
Demantoid garnet is the most important stone of the andradite type of garnet. Some rich grass- green stones owe their color to a slight replacement of the iron in the structure by chromium.
Green Garnet is a Demantoid garnet. They are a rare variety of andradite and have characteristic inclusions that look like horsetails.
Greenstone is another name for nephrite, a variety of jade. It is often veined and used in carvings.
Garnet is a term used for a group of six minerals with similar characteristics: pyrope, almandine, grossularite, spessartite, andradite and uvarovite.
There are six species of garnet - almandine (wine red), pyrope (brownish to orange red), spessartine (orange brown to golden brown - root beer color), andradite (yellowish brown to green), grossular (colorless to green, including yellow, ...
Garnet Stones are available in varieties named Grossularite, Pyrope, Almandine, Rhodalite, Andradite, Essonite, Tsavorite, Spessartite, Melanite, Allochroite, Ouvarovite and Demantoid.
Garnets are one of the few gems that are rarely treated to enhance color or clarity. In rare instances green andradite garnets may be heated to enhance colors.
g: the green andradite garnet (also called Demantoid and commonly confused with emerald) has an R.I of 1.88 and therefore will not show a reading at all in the Refractometer (since a Refractometer will only take readings up to 1.81).
Demantoid: A small, rare, bright and glittering green variety of garnet of the andradite family first mined in the mid-nineteenth century.
Demi-hoop: see Half-hoop design.
Garnet has a number of varietal names depending on color and composition. Examples include almandite, pyrope, rhodolite, grossular, uvarovite, spessartine, andradite, and demantoid.
These precious gemstones were name after the seeds of a pomegranate. Some variations of garnets include Allochroite, Almadine, Andradite, Demantoid, Essonite, Grossularite, Melanite, Ouvarovite, Pyrope, Rodalite, Spessartite, and Tsavorite.
The "garnet group" is divided into six common varieties that are identified by their chemical composition and/or distinct color. The six main garnet types are almandine, andradite, grossularite, pyrope, spessartite, and uvarovite.
Several varieties are known of this rare garnet, the best known of which is demantoid. Topazolite is an obsolete name once applied to yellow andradite.
Demantoid ...
The most commonly found and popular types are almandine and
pyrope, but lesser known and more rare varieties are spessartine, uvarovite, hessonite and andradite.
mineral, garnet, is part of a group of semi precious stones, which range in color from red to green. Occurring in all colors but blue, they have a hardness that varies between 6-8 on the Mohs Scale. Several types of garnets are: Almandine, Andradite, ...
The ugrandite subgroup thus contains grossularite (Ca3Al2(SiO4)3), andradite (Ca3Fe2(SiO4)3), and uvarovite (Ca3Cr2(SiO4)3).
 See also: Garnet, Stone, Color, Mineral, Gemstone
  
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