A play of color
Opal
Hydrated silica material; precious opal shows play-of-color and common opal does not.
Opal is hydrated silica.
Read the specimen guideThe mineral atlas
Rocks and extended assortment
Continue into rocks, unusual mineral specimens, and the wider crystal-shop assortment. The guides separate a rock assemblage from its constituent minerals and explain the evidence behind uncommon trade names.
20 specimens · Geology, history, and attributed traditions
Impact glass landscapes
Moldavite and Tektites
Natural impact-generated glasses derived from terrestrial material.
Moldavite belongs among tektites: natural glasses made from terrestrial material during a major impact event.
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Green and salmon grains
Unakite
Altered rock combining feldspar, epidote and commonly quartz.
Unakite is a mixed rock rather than one pink-green mineral.
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Dark spots pale ground
Dalmatian Stone
Spotted ornamental rock; analyzed trade samples contain a feldspar-quartz matrix with arfvedsonite-rich dark areas.
Dalmatian stone is a spotted decorative rock.
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Dark green circles
Kambaba Stone
Green-and-black orbicular rhyolitic rock in the documented trade material.
Kambaba stone is a green-black decorative trade material.
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A volcanic color field
Rhyolite and Patterned Volcanic Stones
Silica-rich volcanic rock, with varied textures and mineral mixtures.
Rhyolite is a volcanic rock category, not one mineral species.
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A coarse indigo mosaic
Gabbro / Indigo Gabbro
Gabbro is a coarse-grained mafic igneous rock; indigo gabbro is a trade label.
Gabbro is a coarse-grained mafic igneous rock.
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Bronze fiber light
Bronzite
Bronzy-shimmering orthopyroxene material associated with the enstatite–ferrosilite series.
Bronzite is a familiar ornamental name for iron-bearing orthopyroxene material in the enstatite–ferrosilite range.
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A dark metallic sheen
Hypersthene
Legacy name within the enstatite–ferrosilite series, retained in gem trade.
Hypersthene persists in ornamental trade although modern pyroxene classification does not treat it as one independent species.
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Small lights in dark rock
Nuummite
Iridescent amphibole-bearing metamorphic rock associated with Nuuk, Greenland.
Nuummite is a rock associated with anthophyllite and gedrite amphiboles, rather than one standalone mineral species.
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A radiating spray
Astrophyllite
Titanium-bearing silicate mineral with often radiating golden-brown blades.
Astrophyllite is a titanium-bearing silicate, often seen as golden-brown blades against a contrasting host.
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Blue black needles
Arfvedsonite
Sodium-rich amphibole mineral commonly in alkaline igneous rocks.
Arfvedsonite is a sodium-rich amphibole mineral.
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Square light
Apophyllite
A group of hydrous silicate minerals.
Apophyllite is a group name covering related hydrated silicate minerals.
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Sheaves and needles
Zeolites: Stilbite and Scolecite
A family of hydrated aluminosilicates; species differ.
Zeolites are a mineral family, not one pale crystal species.
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The clear wedge
Danburite
Calcium borosilicate mineral.
Danburite is calcium borosilicate, CaB2(SiO4)2.
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Salt in cubes
Halite
Sodium chloride mineral, occurring in evaporite deposits.
Halite is the mineral sodium chloride, NaCl.
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A pale blue network
Larimar
Blue pectolite trade material from the Dominican Republic.
Larimar is trade language for blue pectolite material from the Dominican Republic, not a separate mineral species.
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The eight faced gem
Spinel
Magnesium aluminium oxide mineral.
Spinel is magnesium aluminium oxide, MgAl2O4.
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Crossed crystal forms
Staurolite / Fairy Crosses
Iron-rich aluminium silicate, sometimes naturally twinned into cross-like forms.
Staurolite is an iron-rich aluminium silicate.
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Yellow black and honest names
Bumblebee Stone
Carbonate-rich Indonesian decorative rock, despite the common jasper label.
Bumblebee stone is a carbonate-rich mixed material, despite the common jasper trade name.
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