Magnesite
Magnesite is a magnesium carbonate mineral. In its natural state it is usually white, grey or cream, often with a porous, chalky look and a network of fine grey or brown veins. It forms where magnesium-rich rocks such as serpentine are altered by carbon dioxide-bearing water, and also in some sedimentary deposits. Industrially it is an important source of magnesium oxide, used to line furnaces and kilns.
In jewellery, magnesite is best known for its ability to absorb dye. Because it is porous and has a veined pattern similar to turquoise, white magnesite is very often dyed blue or green and sold as an imitation of turquoise. It is also dyed in a wide range of bright colours such as red, pink, purple, orange and yellow, and dyed magnesite is sometimes sold under names such as "howlite", "turquenite" or simply as dyed or stabilised turquoise. When buying turquoise, a scratch or acetone test on an inconspicuous spot can reveal surface dye.
Magnesite is often confused with howlite, another white, veined mineral that is also dyed to imitate turquoise. The two look very similar but are different minerals. Rare transparent crystals of magnesite are faceted for collectors, but these are not found in beads.
Most magnesite beads are stabilised with resin to strengthen them and improve their polish.
Magnesite at a glance
| Colour | White, grey, cream with grey veins; widely dyed in many colours |
|---|---|
| Hardness (Mohs scale) | 3.5 – 4.5 |
| Composition | Magnesium carbonate |
| Crystal structure | Trigonal; usually massive or porcelain-like |
| Lustre | Vitreous to dull; porcelain-like |
| Transparency | Opaque (rarely transparent crystals) |
| Where it is found | China, Zimbabwe, Brazil, Austria, Russia, Turkey, Canada and USA |
Caring for magnesite
Magnesite is soft (3.5 – 4.5 on the Mohs scale) and porous, and most beads are dyed. Clean it gently with a soft, damp cloth only. Avoid soaking, ultrasonic and steam cleaners, as water and heat can remove or spread the dye. Keep it away from perfume, cosmetics, cleaning products and acids, and avoid long exposure to sunlight, which can fade dyed colours. Store separately in a soft pouch.
In folklore
The beliefs below are traditional folklore, included for interest. They are not scientifically proven, and nothing here is medical advice.
Magnesite has little ancient folklore attached to it, as it was mainly an industrial mineral until recent times. In modern tradition it is associated with peace, positive thinking and the ability to love oneself. Its calming reputation means it is sometimes used as a meditation stone. It is associated with the zodiac sign Libra.
Magnesite is traditionally regarded as a calming stone. Crystal healing lore holds that it relieves stress, irritability and impatience, encourages relaxation and meditation, and helps the wearer approach situations with tolerance and understanding. It is linked to the crown chakra.
Related stones
Howlite, turquoise, calcite, dolomite and serpentine. Dyed magnesite is widely used to imitate turquoise. Lemon chrysoprase (yellow-green and veined) is actually magnesite with nickel colouring.
For the technically minded
| Scientific name | MgCO3 |
|---|---|
| Density | 3.0 – 3.2 |
| Refractive index | 1.509 – 1.700 |
| Double refraction | 0.191 |
| Cleavage | Perfect rhombohedral |
| Streak | White |
| Fluorescence | Pale green to pale blue; may phosphoresce |