Two-phase inclusions in tourmaline from Namibia

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

Twin-crystal of chrysoberyl

Inclusions of hematite in feldspar (sunstone), India

Stress fissure («sun spangle») in baltic amber

Agate from Reichweiler, Germany

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

Agate from Anzi, Maroc

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