Gemology: M is for ...
We've reached the halfway point of our Gemology guide! This week we bring you gemstones beginning with M... Mabe Pearls, Malachite, Marcasite, Maw Sit Sit, Moldavite, Moonstone, Morganite, Moonstone, Mother-of-Pearl and Mystic Topaz.
Mabe Pearls, like all pearls, are an organic gemstone. Most pearls grow from an irritant on the flesh of an oyster or mollusc. The mollusc will then secrete a 'nacre' all over the irritant to form the pearl. The difference with mabe pearls is that the irritant is not on the flesh of the mollusc, but on the inner surface of the shell. This results in a dome shaped pearl with a flat bottom. Depending on how long the pearl has had to form, it could be an irregular blister shape, or a perfect rounded hemisphere.
Malachite is actually the same substance that forms the green 'rust' on copper, but in its gemstone form it can be polished into beautiful cabochons. Malachite can be found in slabs large enough to carve into statues or even use as a gorgeous green bench top! Ancient Greeks, Romans and Egyptians prized malachite for jewellery, and would even grind it to a powder for eye shadow. There are a number of myths and legends surrounding the humble malachite: in the middle ages it was believed that malachite would protect the wearer from the evil eye; Russian legends stated that drinking from a malachite cup would enable a person to communicate with animals; and many cultures believe malachite can attract money.
Marcasite Marcasite is an iron disulphide (sorry for getting technical on you!), but the marcasite in marcasite jewellery isn't marcasite at all - it's a different form of iron disulphide called Pyrite (also known as 'Fool's Gold'). Marcasite is unstable and prone to decomposition that forms a chalky coating, so it really isn't suitable for jewellery at all. Pyrite, on the other hand, is stronger and more stable, and forms a shiny metallic golden shimmer, which is highly desirable for jewellery use. 'Marcasite' was very popular in jewellery in Victorian times when black became the most fashionable colour following Prince Albert's death, but Grandma's antique marcasite jewellery is most likely to be fool's gold.
Maw Sit Sit
Maw Sit Sit is a relative newcomer to the gemstone market, having been identified as a separate distinct mineral composition by gemologist Eduard Gubelin in 1963. Maw Sit Sit is similar to jade but has a different make-up, being formed of up to six different minerals. The unusual name comes from the Burmese village near which it was located, and which remains the only place where Maw Sit Sit can be found. Maw Sit Sit is a rich dark green, marbled and mottled by black veining. It's a very rare mineral gemstone, and very beautiful as a dramatic jewellery piece.
Moldavite is a rare gemstone that made its way from outer space all the way to Czechoslovakia! The Moldau River in the Czech Republic is the only place this mineral has ever been found, and it arrived there in a meteorite, possibly over 14 million years ago. Moldavite has a glassy appearance, owing to its silica content, with long bubbles and waves throughout. It was first recorded in 1787, though it has been used for decorative purposes for thousands of years.
Moonstone is one of the most famous and legendary gemstones. It's a form of feldspar that occurs in shades of ethereal white, blue, and even pale peach tones. The rarest form, and most mystical, is a clear stone with a blue shimmer that seems to be both inside and outside the stone at the same time, like a moon glow. This strange property is known as adularescence. Moonstone is one of the birthstones for June, and there are many myths and legends attached to its uses. You can read more about this in our upcoming June birthstone article.
Morganite Morganite is a newcomer to the gemstone market, but its reputation and popularity is growing very fast. First identified in Madagascar in 1910, large deposits of high quality morganite have since been found in Brazil, with other smaller deposits found in Africa. Another form or beryl, like emerald and aquamarine, morganite is pink-peach to bright peach translucent gemstone that can grow to immense sizes - up to 10kg! The largest faceted morganite gemstone weighs 600 carats, and can be found in British Museum
Mother-of-Pearl Mother-of-Pearl has been used for decorative purposes for thousands of years. Mother-of-Pearl is the iridescent shimmering lining of oyster and mollusc shells, so it's not technically a gemstone, but it is still popular in jewellery. The colour can range from a pale pearlescent shimmering cream, to a rainbow of colours like that found inside Abalone shells. Mother-of-Pearl is formed from nacre - the same substance that forms the surface of pearls – but it doesn't form in pearl shapes. It's carved from the inside of mollusc so is often used as an inlay
Musgravite Musgravite is one of the rarest gemstone quality minerals, with only EIGHT facetable gemstone specimens found between its discovery in 1967 and 2005. It's named for the Musgrave Ranges of South Australia where it was first discovered, but has since been found in Greenland, Madagascar, Antarctica, Sri Lanka and Tasmania. Musgravite is part of the Taaffeite family – another extremely rare mineral – and only a special test using x-rays can tell the two apart. Musgravite occurs in shades of light olive to mauve. Prices for good quality Musgravite can range from $6,000 to $35,000 per carat depending on cut and colour, making it more
Mystic Topaz Mystic Topaz is named for it's shimmering mystic colours, but the colours are artificially applied to a colourless topaz to make it more desirable. The technique, perfected in 1988, applies a microscopically thin layer of titanium to plain topaz to create and amazing rainbow light refraction. Because the colours are artificially applied, great care should be taken when cleaning your mystic topaz to preserve it's 'mystical' coating. Mystic Topaz is a new birthstone for those born in November.