Colour zoning in ruby from Mong-Shu, Burma

Midge included in amber from the Baltic coast, polarised light

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

Partially etched diamond crystal

Two-phase inclusions in tourmaline from Namibia

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

Fluid inclusions in quartz with bituminous daughter minerals, China

Stress fissure («sun spangle») in baltic amber

«Red fox agate» from Patagonia, Argentina