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

Inclusions of fossil plant debris in opal from Wollo, Ethiopia

Fluid inclusions in quartz with bituminous daughter minerals, China

Spinel crystal in dolomite marble, Burma

Stress fissure («sun spangle») in baltic amber

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

Twin-crystal of chrysoberyl

Agate from Anzi, Maroc

Partially etched diamond crystal