Dumortierite in rock crystal, Brazil, polarised light

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

Inclusion of apatite in ruby from Tanzania

Fluid inclusions in quartz with bituminous daughter minerals, China

Midge included in amber from the Baltic coast, polarised light

Agate from Reichweiler, Germany

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

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