Andradite - characteristics, varieties, properties and influence on the signs of the Zodiac

One of the silicates of the garnet group is the mineral andradite, named after the Brazilian scientist José de Andrada. The stone is quite widespread; its beautiful crystals of rhombic dodecahedral or tetragontrioctahedral shape can be easily distinguished by the unusual shading on the faces. Andradites are found in the form of intergrowths, druses and crystalline crusts in rock cracks, less often - as veinlets, individual grains or inclusions.

Andradite deposits

Deposits of high-quality jewelry andradites are located in Namibia, Congo, Iran, India, and Afghanistan.
Large deposits are being developed in countries such as Italy, Finland, Norway, and Germany. — Advertising —

Well-known andradite mines are the USA (California, Alaska, Arizona, New Jersey, Idaho) and Canada, as well as Russia (Urals, Karelia, Kola Peninsula, Krasnoyarsk Territory, Kamchatka, Chukotka). One of the unusual iridescent varieties of the mineral is mined in Mexico.

Mineral Change

Under the influence of hydrothermal solutions, it is replaced by other minerals, especially serpentine, chlorites, epidote, actinolite, hematite, sometimes prehnite, magnetite, titanite, albite, and hornblende. In the skarns of the Turinsky mines (Urals), andradite was altered with the formation of finely disseminated pyrite, quartz, calcite and magnetite. In the hypergenesis zone, the mineral may lose some iron; nontronite, brown iron hydroxides and opal are noted as products of its weathering.

Place of Birth

History of andradite

Jose de Andrada, originally from Brazil, during his life managed to be noted for military, political, and scientific successes.
He even happened to be the tutor of the young Emperor of Brazil. But one of his most serious and favorite hobbies was the science of mineralogy. The scientist became the discoverer of four stones, one of which was later named after him - andradite.

Physico-chemical characteristics of andradite

Chemically, andradite is a calcium-iron variety of garnet.
Like related minerals, it forms crystals with rhombic or trapezoidal facets or combinations thereof. — Advertising —

Natural andradites are always isometric. Their color palette is quite diverse: from green, red-brown, brown, yellow to black. The crystals are fragile with a glassy luster.

The hardness of the crystals on the Mohs scale is 6.5-7.0. Density is in the range of 3.81-3.87. Refractive index from 1.855 to 1.895. There is no birefringence, luminescence or pleochroism. The variance is 0.057

Andradites can be of varying degrees of transparency; they are characterized by cubic system and lack of cleavage. At the fracture, the crystals are conchoidal and splintered.

Types of andradite

Andradite belongs to the ugrandite family, which includes calcium-containing garnets (they also include uvarovites and grossulars). Depending on the appearance and characteristics of the mineral, the following types are distinguished:

• Allochroite is a nondescript stone, colored from brown and reddish-brown to black. In ancient times, this variety was considered medicinal, but poorly colored, and was used to make home decorations. Among the Norwegians, allochroites symbolized trolls. It was believed that the latter protected houses where candlesticks were made of this mineral.

• Topazolites have a yellow tint, making the stone look like amber. Because of this, they were previously called succinites, but they were valued low. Nowadays, pure, transparent crystals are used as jewelry stones and are valued quite highly.

• Demantoids are one of the most valuable varieties of greenish andradite.

• Shorlomites are distinguished by their titanium oxide content. They are dark gray in color with a pronounced shine - from glass to diamond-like. Shorlomite is sometimes known as “pearl” garnet and is used in jewelry.

• Melanite - andradite is almost black in color. The content of titanium oxide in this variety of andradite is the highest. The stone has a rich color and beautiful shine, and after careful polishing it looks like a black mirror. Very popular in European countries.

• Colophonite, a reddish-colored andradite, and jelletite, a marsh-green variety, are lesser known and are not usually used in jewelry.

Artificial acquisition.

Synthesized from a mixture of wollastonite, Fe2O3 and FeCl3 at a pressure of 20,000 atm and 900°. From a mixture of powders of the corresponding oxides it was obtained at 1280° and atmospheric pressure (for 720 hours), as well as at 480° and a pressure of 150 atm (about 500 hours). High-temperature hydrothermal synthesis from a mixture of CaCO3, Fe(OH)3, SiO2 (amorphous) in a 5% solution of Na2CO3 was carried out at a pressure of 400-800 atm and a temperature of 600-700°. Together with wollastonite, it was obtained by heating a mixture of the composition 3SiO2* Fe2O3-3CaO to 500° at a water vapor pressure of 500 bar. From a mixture of Ca(OH)2, Fe2O3 and SiO2 in chloride solutions (CaCl2, NH4Cl) in the presence of Na2B4O7 was obtained at 255-280° and a pressure of 1500 atm; when replacing Ca(OH)2 with CaCO3, the temperature of andradite formation increased to 460-475°.

Studied in the system 3CaСO3—Fe2O3—3SiO2; synthesized at a pressure of 500 atm in a 5% NaCl solution and a temperature of 500° for 5-7 hours. and 600° for 45-50 minutes. It can occur during the crystallization of glass of the appropriate composition, during the crystallization of a rock containing 60% alkali feldspars and 35% chlorite, at a water vapor pressure of 1000 bar and a temperature of 600°. Installed as part of silica bricks in steelmaking furnaces.

Diagnostic signs

By external signs, it is easily recognized by the characteristic appearance of crystals, luster, high hardness and relatively high specific gravity.

Satellites. quartz, calcite, scapolite, plagioclase, orthoclase, olivine, hornblende, chlorite and microcline-perthite epidote, diopside, zoisite, actinolite, pyroxene.

Magical properties of andradite

In Medieval Europe, andradites were popular among both female and male warriors. Knights often used gems as talismans and amulets, since there was a legend that andradite protected its owner from dangerous injuries and death on the battlefield.

Later, andradite was endowed with the properties of ridding the owner of bad thoughts, averting dangers and troubles, and also preventing betrayal of loved ones.

In addition, andradite is known as the “stone of seduction.” He is an excellent assistant in winning the attention of others, conquering them with charm, and is also capable of causing the manifestation of serious passions. In this regard, the mineral has a greater influence on women, endowing them with sensitivity and dreaminess, romance and seductiveness.

According to ancient legends, andradite allows its owner to gain power over people and control them. Its ability to give happy love and a wonderful life to spouses is also known.

Origin and location

The mineral is widely distributed. It is most typical of skarns. Andradite occurs in igneous rocks, pegmatites, hydrothermal veins, and regionally metamorphosed rocks. Andradite skarns usually accompany magnetite deposits of contact origin: Mount Magnitnaya, Mount Vysokaya, Mount Blagodat (Ural), Dashkesan (Azerbaijan), etc. The formation of andradite in metamorphic rocks indicates an increased oxygen potential. The formation of andradite could most easily occur in rocks containing quartz, calcite and magnetite. According to experimental data, the optimal conditions for replacing calcite with andradite are low partial pressure of CO2 and a temperature of about 600°. With a lack of calcium and a large amount of silica, the mineral does not form, but minerals with a low calcium content are formed (hornblende, hypersthene, cordierite, sillimanite, biotite). It is not observed together with more ferruginous pyroxene, since in this case magnetite, quartz, calcite and pyroxene of intermediate composition are formed.

The formation of demantoid is associated with the interaction of mafic magma and limestones in deep conditions.

Healing properties of andradite

In lithotherapy, it is believed that andradite, in contact with the skin, takes away the negative energy of destruction from the internal organs.
The stone is used in the treatment of diseases of the respiratory system: bronchitis, asthma, laryngitis, tonsillitis, pneumonia. To cure serious illnesses, it is recommended to wear beads or a pendant with this gem around your neck all the time. In addition, andradites are used to relieve pain from migraines, depression, and to stop severe bleeding.

How to care

Like a typical garnet, andradite is hard but brittle. You need to take care of your jewelry very carefully:

• Store in a separate box.
• Avoid falls, impacts, and contact with chemicals.
• Keep away from direct sun: the stone will fade.
• Do not wear jewelry to the beach, sauna, or steam room: the inserts will crack.

When cleaning the product, use warm water, soap solution, and a soft cloth. Chemicals, abrasives, and steam cleaning are prohibited.

Ring with andradite

Branches of application of andradite

Most varieties of andradite have not found practical application; their beautiful, regular-shaped crystals and druses are popular mainly as decorative and collectible objects.
Such types of gems as demantoid and topazolite are recognized as jewelry stones. In order to maximize their properties and reveal their natural beauty, the stones are subjected to thermal refinement. At the same time, the overall color tone becomes more saturated, and the crystal itself acquires exquisite transparency.

For refining, demantoid or topazolite is placed in a graphite crucible and heated to 850°C. Color saturation and transparency are clearly observed only for small-sized crystals, but samples larger than 3-4 carats often crack during this procedure.

Andradites are quite fragile stones, they do not tolerate stress well and require care in processing and daily wearing of jewelry.

Compatibility with zodiac signs

(“+++” – the stone fits perfectly, “+” – can be worn, “-” – is strictly contraindicated):

Andradite, like garnet, is ideal for Aquarius and Scorpio; the stone is also suitable as a talisman for other zodiac signs. The mineral is not suitable for Capricorn, Pisces, Aries and Virgo.

Reference! Lazy people should not buy andradite - it is absolutely powerless in front of them. But it will help active people not only increase, but also correctly direct their energy.

Is this stone right for you?

Interesting facts about andradite:

• Andradite talismans are recommended primarily for women in order to become the center of attention of any company and easily win the favor of men. The stone truly attracts attention and creates a string of admirers for its owner, who will become loved and fall in love herself, and the union sealed with andradite will certainly be successful and happy.
• Andradite is considered the stone of talented and creative people; artists, poets, musicians, sculptors and fashion designers use it very often. It is believed that this gem brings creative inspiration and accompanies career success. But its owner must devote maximum attention to his profession.
• In dangerous situations, andradite adds composure to its owner and helps to cope with any adversity.
• Andradite amulets are rings and pendants, or small gems that are worn in a pocket.

Interesting things about the stone

Andradite will be very useful for creative people - artists, musicians, poets, etc. It will bring them luck, discovery of talent and career growth.

This stone is very effective for women - it gives them charm and self-confidence, thanks to which they blossom to their full potential. In addition, the green stone looks very impressive on those with brown and green eyes.

Andradite helps men maintain sanity and composure, develops intuition and helps with making the right and rational decision.