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

Dumortierite in rock crystal, Brazil, polarised light

Agate from Anzi, Maroc

Two-phase inclusions in sapphire, Sri Lanka

Agate from Reichweiler, Germany

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

«Red fox agate» from Patagonia, Argentina

Spinel crystal in dolomite marble, Burma

Two-Phase inclusions and rutile needles in rock crystal from Brazil