Starstruck8
Brilliant_Rock
- Joined
- May 13, 2021
- Messages
- 797
OK, so here's a rainbow gem - rainbow lattice sunstone. You can call this any colour you like. Actual size is about 12x9mm.

Strictly, it's moonstone (orthoclase feldspar), but it's marketed as rainbow lattice sunstone. It is found only in Harts Range, Northern Territory, Australia. The inclusions are long, very thin crystals of magnetite and hematite, which are oriented to the crystal axes of the moonstone. The iridescent colours are produced by interference, because the inclusions are so thin (sub-micron).
Those who dare can read about it here (serious geek alert!): https://ejm.copernicus.org/articles/34/183/2022/ejm-34-183-2022.pdf
If you are thinking of buying some, be aware that to see the colours, you need the stone and the lighting at just the right angle, so it's more a collector's stone than something you would wear. In any case, feldspar is a bit soft, hardness 6.

Strictly, it's moonstone (orthoclase feldspar), but it's marketed as rainbow lattice sunstone. It is found only in Harts Range, Northern Territory, Australia. The inclusions are long, very thin crystals of magnetite and hematite, which are oriented to the crystal axes of the moonstone. The iridescent colours are produced by interference, because the inclusions are so thin (sub-micron).
Those who dare can read about it here (serious geek alert!): https://ejm.copernicus.org/articles/34/183/2022/ejm-34-183-2022.pdf
If you are thinking of buying some, be aware that to see the colours, you need the stone and the lighting at just the right angle, so it's more a collector's stone than something you would wear. In any case, feldspar is a bit soft, hardness 6.