Bi-colour gemstones show two distinct colours in one stone, formed naturally as the crystal grew. Well-known examples are bi-colour tourmaline, ametrine with its purple and gold halves, and bi-colour sapphire.
How to choose a bi-colour gemstone
- Look at the split: a clean, even line between colours is usually the most sought-after look.
- Check the balance: decide whether you want equal halves or one colour leading.
- Choose a long shape: emerald cuts and long ovals show both colours well.
- Mind the setting: an open setting lets light pass through both colour zones.
- Know natural from assembled: true bi-colour stones grow that way, while assembled stones are glued together from two separate pieces.
See bi-colour tourmaline, ametrine and multi-colour gemstones for more stones with mixed colour.