October Birthstones; Tourmaline and Opal At Roseanna Croft Jewellery we love birthstones! Gemstones filled with sentiment that can mean so much to one individual, just because of the month you were born in! And if you were lucky enough to have been in the Autumnal month of October, you have two to choose from! Tourmaline The name “tourmaline” comes from the Sinhalese words tura mali, which mean “stone of mixed colours.” As the name says, Tourmaline is different from other gemstones as it has a varied spectrum of colours in all shades of the rainbow. It isn’t one mineral, but a complex group of minerals, all with different chemical compositions and properties. Certain elements produce certain colours, and a lot of these resulting varieties have their own names.