Stress fissure («sun spangle») in baltic amber

Colour zoning in ruby from Mong-Shu, Burma

Dendrites in agate

Dumortierite in rock crystal, Brazil, polarised light

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

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

Structure in a healing fissure in topaz from Brazil

Inclusions of hematite in feldspar (sunstone), India

Fire opal, Mexico