Colour in gemstones: quick notes

Some useful hand notes to distinguish terminology used to describe the optical effects that cause colour and colour phenomena in gemstones. It’s important to know your spectral colour effects like fire and iridescence and distinguish between pleochroism, iridescence and colour change. The cover image shows the two body colours (dichroism) that combine in a ruby:… Continue reading Colour in gemstones: quick notes

Spinel: quick notes

The lesser-sung cousins of corundum like sapphires and rubies, spinels are resilient gemstones that come in a variety of colours from greys and purples to ‘Jedi’ red. Here are some quick geological facts to get you started with this beautiful gem material. Note: Don’t get confused with synthetic (lab grown) spinel, commonly coloured blue with… Continue reading Spinel: quick notes