Iolite has a rich deep indigo blue, like sapphire, but is a fraction of the price, we love it as an alternative. Not seen them used in jewellery that much so we're collecting up some fine ones before everyone else finds out and the price goes up. Iolite is one stone that displays pleochroism which is an optical phenomenon where the stone appears to be different colours when observed from different angles, especially with polarized light. This gives the tinge of purple in the greyish blue stone extra depth and intrigue. Although it often has an inky inclusion or two, it doesn't really cloud so is nice and sparkly. Truly flawless iolites are quite rare and get more expensive but they are still one of the more affordable dark stones.
Fun fact: iolite has been dubbed the "Vikings' Compass" because of its usefulness in determining the direction of the sun on overcast days. This works by revealing the direction of polarisation of the sky overhead. By looking through the iolite you can see where the sun is even when the sun itself is obscured by fog or lying just below the horizon.
Colours: Indigo, blue/purple
Mohs scale: 7 - 7.5
Crystal Formation: Orthorhombic
Country of origin: Australia (Northern Territory), Brazil, Burma, Canada, India, Madagascar, Namibia, Sri Lanka, Tanzania and the United States