Inclusions of fossil plant debris in opal from Wollo, Ethiopia

Spinel crystal in dolomite marble, Burma

Dendrites in agate

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

Inclusions of chrysotile fibres in demantoide garnet from Ural Mountains, Russia

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

Colour zoning in ruby from Mong-Shu, Burma

Agate from Reichweiler, Germany

Agate from Anzi, Maroc