Structure in a healing fissure in topaz from Brazil

Dumortierite in rock crystal, Brazil, polarised light

Fluid inclusions containing mica and quartz, in aquamarine from Pakistan

Dendrites in agate

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

Twin-crystal of chrysoberyl

Inclusions of rutile (dark crystal and fine needles) and clusters of zircon grains in umbalite garnet, Tanzania

Inclusions of gilalite aggregates in rock crystal from Brazil

Agate from Anzi, Maroc