Tourmaline, Iolite, and diamond ring
Tourmaline, iolite, & diamond ring
A tourmaline, iolite, and diamond ring in 18K gold from our designer collection.
More on tourmaline:
In order to understand this variety of colour, you will have to brush up your knowledge of gemmology a little: tourmalines are mixed crystals of aluminium boron silicate with a complex and changing composition. The mineral group is a fairly complex one. Even slight changes in the composition cause completely different colours. Crystals of only a single colour are fairly rare; indeed the same crystal will often display various colours and various nuances of those colours. And the trademark of this gemstone is not only its great wealth of colour, but also its marked dichroism. Depending on the angle from which you look at it, the colour may be different or more or less intense. It is always at its most intense when viewed looking toward the main axis, a fact to which the cutter must pay great attention when lining up the cut. This gemstone has excellent wearing qualities and is easy to look after, for all tourmalines have a good hardness of 7 to 7.5 on the Mohs scale. So the tourmaline is an interesting gemstone in many ways.
More on Iolite:
The property that made iolite so valuable is its extreme pleochroism. Iolite has different colors in different directions in the crystal. A cube cut from iolite will look a more or less violet blue, almost like sapphire, from one side, clear as water from the other, and a honey yellow from on top. In the past, this property led some people to call iolite ‘water sapphire’, though the name is now obsolete.
Pleochroism may have been helpful in navigation but it certainly makes life difficult for the cutter. If iolite is not cut from exactly the right direction, no matter what the shape of the raw crystal, its color will not be shown to its best advantage.
The name iolite comes from the Greek ‘ion’, which means violet. Iolite is usually a purplish blue when cut properly, with a softness to the color that can be quite attractive.
Iolite is readily available and surprisingly affordable. The richer the blue, the better. It is mined in India, Sri Lanka, Mozambique, Zimbabwe, and Brazil.