Inclusions of gilalite aggregates in rock crystal from Brazil

Bubbles and swirls in moldavite (natural glass)

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

Spinel crystal in dolomite marble, Burma

Dumortierite in rock crystal, Brazil, polarised light

Dendrites in agate

Fire opal, Mexico

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

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