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

Inclusions of gilalite aggregates in rock crystal from Brazil

Midge included in amber from the Baltic coast, polarised light

Dumortierite in rock crystal, Brazil, polarised light

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

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

Agate from Anzi, Maroc

Two-phase inclusions in sapphire, Sri Lanka

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