Partially etched diamond crystal

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

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

Fluid inclusions in quartz with bituminous daughter minerals, China

Dendrites in agate

Inclusions of hematite in aquamarine, Tanzania