Natural etching structure on a crystal face of diamond (trigons), polarised light

Inclusions of anatase crystal and rutile fibres in rock crystal from Brazil

Bubbles and swirls in moldavite (natural glass)

Inclusions of rutile (dark crystal and fine needles) and clusters of zircon grains in umbalite garnet, Tanzania

Colour zoning in ruby from Mong-Shu, Burma

Two-phase inclusion in amethyst, Brazil

Inclusions of rock crystal and rutile needles in quartz, Brazil, polarised light

Inclusions of hematite in aquamarine, Tanzania

Two-phase inclusions in sapphire, Sri Lanka