Rock & Mineral Encyclopedia

Search and identify 1,000+ rocks, minerals, crystals, and gemstones — with properties, formation, colors, hardness, and how to tell them apart.

Flower Agate

A creamy pink-and-white chalcedony from Madagascar containing flower-like plume inclusions that resemble blossoms suspended in stone.

Tourmaline displaying two distinct colors in a single crystal, a natural color-zoning effect that makes each stone unique.

An opaque, iron-rich variety of microcrystalline quartz known for its deep brick-red color and ancient history as a stone of strength and grounding.

Quartz colored blue by inclusions of the mineral dumortierite, giving a denim-like blue ornamental stone harder than dumortierite alone.

A warm golden-to-amber opal ranging from translucent common opal to precious stones that flash play-of-color over a honey body.

Precious opal from the Mintabie field in South Australia, known for hard, bright crystal opal and some dark-bodied stones.

A golden-toned opal ranging from translucent common opal to precious stones flashing color against a warm yellow body.

A glowing orange-to-red opal whose warm body color resembles flame; some stones add flashes of play-of-color.

A tourmaline displaying two or more distinct colors in a single crystal, prized for natural color zoning like watermelon and bicolor stones.

Australia's classic light-bodied precious opal from Coober Pedy, famed for milky white stones flashing pastel rainbow play-of-color.

Sandstone altered by metamorphism, with partly recrystallized quartz grains, transitional between true sandstone and quartzite.

A mica schist containing bladed blue kyanite crystals, a marker of medium- to high-grade metamorphism of aluminous rocks.