Bubbles and swirls in moldavite (natural glass)

Agate from Reichweiler, Germany

Epigenetic inclusion (probanly melanterite) in quartz, Brazil, parallel polarisers

Colour zoning in ruby from Mong-Shu, Burma

Dumortierite in rock crystal, Brazil, polarised light

Agate from Anzi, Maroc

Two-phase inclusion in amethyst, Brazil

Fire opal, Mexico

Partially etched diamond crystal