Fireworks. Jellyfish. Galaxies. Lightning. Opal's shifting play of kaleidoscopic colors is unlike any other gem.
Opal's microscopic arrays of stacked silica spheres diffract light into a blaze of flashing colors. An opal's color range and pattern help determine its value.
Grids of silica spheres 0.2 microns in size create red play-of-color flashes.
The novel "Anne of Geierstein" gave opal a reputation of being unlucky.
Opal contains up to 20% water trapped in its silica structure.
Opal's spectacular play-of-color can display all the colors of the rainbow.
Experts expect different levels of clarity for different types of opals.
Fine opals are often cut into irregular shapes that keep as much play-of-color as possible.
Opal has relatively low density so even larger sizes can be comfortable to wear.