Inclusions of fossil plant debris in opal from Wollo, Ethiopia

Structure in a healing fissure in topaz from Brazil

Two-phase inclusions in tourmaline from Namibia

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

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

Agate from Reichweiler, Germany

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

Dumortierite in rock crystal, Brazil, polarised light

Partially etched diamond crystal