Iolite is a purplish blue sparkly transparent gem composed of magnesium aluminium silicate. It grows in short prism crystals and it is found mainly in Burma, Sri Lanka, and India. Iolite is not a well-known gem, but it is very attractive and durable, making it suitable for rings and jewellery of all types.
Iolite’s rich colour may shine differently from different angles, making it a truly unique and beautiful stone indeed. This property, called dichroism, is a phenomenon also found in Tanzanite which Iolite closely resembles. It differs from the colour change of Alexandrite where the change is due to different source types of light. In the case of Iolite, the viewing angle is the only variable, the type of light remains the same. The orientation of the stone, as it is being cut, can greatly affect the effect.
Iolite is less expensive, perfect for someone who likes the purplish / blue hues of Tanzanite but wishes to stick to a more modest price-point, or wants a larger stone for the same money. But unfortunately, Iolite does not come in very large sizes.
Interestingly, because Iolite transmits light differently depending on the angle, thin slices of this stone can be used as a light polarizer. This means it acts like a selective camera filter, reducing haze or mist to make things look clearer on the other side. Long ago, the Vikings used two slices of Iolite to help navigate their ships, because they could look through it see past the clouds or mist to find the sun’s position. As the slices are rotated, they cancel out certain frequencies of the spectrum and protect the eyes from damage. The same process is used on modern Polarized sunglasses like Blu Blockers.
We stock both unset and finished pieces of Iolite at most times.