The month of October has two beautiful gemstones – tourmalines and opals. So why does October have two birthstones when most other months only have one? The American National Retail Jeweler’s Association (now Jewellers of America (JA)) published the first list of birthstones in 1912, having drawn from a lot of other similar historical types of lists. The opal was the main gemstone for October in that list but the tourmaline was listed as an alternative. But in 1952, the JA agreed to some changes to the birthstones list, one of which was to move the tourmaline next to the opal as a main birthstone for October. They specified a pink tourmaline. I haven’t been able to find why the JA considered that the opal wasn’t enough on its own.
On the face of it, the opal and the tourmaline are quite different gemstones but they do each contain a wide range of colours. The difference is that the opal displays its arrays of colour internally whilst the tourmaline displays it in separate gemstones. Let’s examine the two gemstones, starting with the opal.
Precious opal displays a play of colour against a white, translucent or dark background. It is the background that describes and defines the type of opal. Black opal has a black, brown or dark gray background, white opal has a white or cream background and crystal opal is translucent. The play of colour is a display of iridescent colours – blue, green, yellow and/or red – which change depending on the direction you hold the gemstone.
Opals are the second gemstone for October. Precious opal displays a play of colour against a white, translucent or dark background. It is the background that describes and defines the type of opal. Black opals has a black, brown or dark gray background, white opal has a white or cream background and crystal opal is translucent. The play of colour is a display of iridescent colours – blue, green, yellow and/or red – which change depending on the direction you hold the gemstone.
In antique jewellery, the most common precious opals found are white or crystal opals as black opals from Australia were not commercially mined until 1903. White opals have a white or creamy background with play of colour. A crystal or water opal refers to any kind of opal which has a transparent, translucent, or semi-translucent body. Because opals are quite soft and can crack easily, they are usually cut as cabochons.
Antique opals were mined in Czernewitsa in Hungary, in what is now Slovakia. Later they were mined in Honduras and Mexico and from the USA from the late 19th century. Popular with the Romans and for a number of centuries following, opals became associated with bad luck from the late 17th century until the middle to late 19th century. They became appreciated again with the rise of Art Nouveau and Belle Epoque jewellery as the delicate colours of opals suited the new styles of jewellery perfectly.
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Tourmalines are a bit of an overlooked gemstone. They come in a stunning range of colours – from greens, pinks, yellows, browns, blues, black, and lilac, to the red version called rubellite. The paraiba, originally found in Brazil but now also from Nigeria, and Mozambique, is a vivid blue to green stone. There are also the lovely part-coloured ones, like the watermelon tourmaline which is green on the outside and pink in the middle. It has a very long history as a gemstone, but it was not specifically identified as a separate gemstone family until the early 1700s. Before then, it was assumed that if a stone was green, it was an emerald, if blue, a sapphire, red a ruby and pink an amethyst, pink sapphire or topaz.
As I mentioned at the beginning of the post, it is the pink tourmaline that was specifically included as an October gemstone in 1952. So I have included above a photo of this magnificent vintage pink tourmaline ring, with a pearl border.
navette jewellery 