Two-phase inclusions in tourmaline from Namibia

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

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

Inclusions of fossil plant debris in opal from Wollo, Ethiopia

Stress fissure («sun spangle») in baltic amber

Twin-crystal of chrysoberyl

Structure in a healing fissure in topaz from Brazil

Agate from Reichweiler, Germany

Bubbles and swirls in moldavite (natural glass)