Epigenetic inclusion (probanly melanterite) in quartz, Brazil, parallel polarisers

Stress fissure («sun spangle») in baltic amber

Two-phase inclusion in amethyst, Brazil

Dumortierite in rock crystal, Brazil, polarised light

Twin-crystal of chrysoberyl

Fluid inclusions containing mica and quartz, in aquamarine from Pakistan

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

Inclusions of hematite in aquamarine, Tanzania

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