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

Agate from Reichweiler, Germany

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

Inclusions of fossil plant debris in opal from Wollo, Ethiopia

Partially etched diamond crystal

«Red fox agate» from Patagonia, Argentina

Inclusions of anatase crystal and rutile fibres in rock crystal from Brazil

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

Inclusions of rock crystal and rutile needles in quartz, Brazil, polarised light