The crystal encyclopedia

Red and iron stones traditionally carried before something difficult.

Pyroxene

Aegirine

Long, sharply striated black-green prisms, most famously from Mount Malosa in Malawi, where they grow with orange zircon and smoky quartz in some of the most photogenic combination specimens of recent decades.

Mohs 6-6.5 · Black, Black-green

Silicate

Andalusite

A strongly pleochroic gem that shows green, gold and red-brown simultaneously from different directions — cutters deliberately orient it to display all three at once rather than trying to eliminate them.

Mohs 7-7.5 · Olive green, Brown

Beryl

Aquamarine

Blue beryl, colored by iron, and the same mineral species as emerald and morganite. Crystals grow as long hexagonal prisms with flat terminations and can reach enormous size.

Mohs 7.5-8 · Blue, Blue-green

Amphibole

Arfvedsonite

A dark sodium amphibole that carries a startling blue-to-gold flash along its cleavage — sold widely and inaccurately as 'nuummite', which it superficially resembles.

Mohs 5-6 · Black, Iridescent

Chalcedony

Bloodstone

Dark green chalcedony flecked with red jasper. Also called heliotrope, it is one of the traditional March birthstones.

Mohs 6.5-7 · Green, Red

Pyroxene

Bronzite

Enstatite with enough iron to develop a warm metallic bronze sheen across the cleavage planes. Usually cut as cabochons or beads, sometimes intergrown with green serpentine.

Mohs 5-6 · Bronze, Brown

Sedimentary

Bumblebee Stone

Banded yellow, orange and black material from a live volcanic fumarole field in Java. Sold as 'bumblebee jasper', but it is not a jasper at all — it is volcanic sediment cemented with sulfur, calcite and arsenic minerals.

Mohs 4-5 · Yellow, Black

Chalcedony

Carnelian

Translucent orange to deep red chalcedony colored by iron oxide. Warm, glowing and tough, it has been one of the world's favourite carving stones for millennia.

Mohs 6.5-7 · Orange, Red

Silicate

Charoite

Swirling fibrous violet silicate found only along the Chara River in Siberia. The chatoyant feathered patterning is unmistakable.

Mohs 5-6 · Violet, Purple

Sulfide

Cinnabar

Mercury sulfide, and the most saturated natural red in the mineral kingdom. Chinese crystals on white dolomite are the specimens collectors want; the massive ore was the world's source of mercury and of vermilion pigment.

Mohs 2-2.5 · Red, Pink-red

Quartz

Citrine

Yellow to golden quartz. Genuinely natural citrine is uncommon and tends toward a smoky lemon or champagne tone; the vivid orange 'burnt' material widely sold is heat-treated amethyst, which is a legitimate product but a different thing entirely.

Mohs 7 · Yellow, Golden

Chromate

Crocoite

Tangerine-orange lead chromate in hollow sprays of hair-fine prisms. Tasmanian Dundas material is the world standard and among the most photographed minerals in existence.

Mohs 2.5-3 · Orange, Red

Oxide

Cuprite

Copper oxide in deep garnet-red cubes and octahedra that glow ruby when back-lit. Namibian Onganja crystals from the 1970s are legendary; the hair-like variety chalcotrichite forms scarlet velvet mats.

Mohs 3.5-4 · Red, Pink-red

Silicate

Epidote

Distinctly pistachio-green striated crystals with a resinous lustre, often forming radiating sprays on quartz or prehnite.

Mohs 6-7 · Pistachio green, Black-green

Arsenate

Erythrite

Cobalt bloom — brilliant magenta needles and crusts that form where cobalt ores weather. Moroccan Bou Azzer specimens with radiating crimson sprays are the classic.

Mohs 1.5-2.5 · Magenta, Pink-red

Silicate

Eudialyte

Raspberry-red zirconium silicate scattered through dark alkaline rock with black aegirine and white feldspar — a striking three-color combination unique to a handful of peralkaline intrusions.

Mohs 5-6 · Magenta, Pink-red

Chalcedony

Fire Agate

Chalcedony containing microscopically thin layers of iron oxide that create iridescent fire — reds, greens and golds — trapped inside the stone. Cutting it is a specialist skill: the cutter must chase the fire layer without going through it.

Mohs 6.5-7 · Brown, Red

Fossil

Fossil Shark Tooth

Sharks shed teeth continuously, which is why they are the most abundant vertebrate fossil on earth. Color comes from the minerals in the burial sediment — river-tumbled Florida teeth run jet black, Moroccan phosphate teeth tan and grey.

Mohs 4.5-5 · Black, Grey

Garnet group

Garnet

A family of related silicates rather than one mineral, spanning almandine red, tsavorite green, spessartine orange and color-changing pyrope-spessartine. Crystals grow as dodecahedra with striking geometric perfection.

Mohs 6.5-7.5 · Red, Green

Beryl

Heliodor

Golden beryl, colored by iron — the sunlit member of the family that also gives emerald, aquamarine and morganite. Ukrainian Volyn crystals are the classic: sharp hexagonal prisms in champagne to deep gold.

Mohs 7.5-8 · Golden, Yellow

Impactite

Libyan Desert Glass

Almost pure silica glass, twenty-nine million years old, scattered across a remote corner of the Sahara by an impact event that has never been fully resolved.

Mohs 6-7 · Pale yellow, Clear

Volcanic glass

Mahogany Obsidian

Obsidian streaked with red-brown iron oxide bands, giving a marbled timber-like figure through the black glass.

Mohs 5-5.5 · Mahogany, Black

Fossil

Megalodon Tooth

The tooth of Otodus megalodon, the largest shark that ever lived, extinct around 3.6 million years ago. Teeth run from palm-sized to over seven inches; every extra half inch above five is a substantial jump in rarity and price.

Mohs 4.5-5 · Black, Grey

Fossil

Mosasaur Tooth

The conical, ridged tooth of a Cretaceous marine reptile — a lizard that returned to the sea and grew to seventeen metres. Moroccan phosphate beds supply most of the market, often with root and jaw section intact.

Mohs 4.5-5 · Brown, Black

Meteorite

Nickel-Iron Meteorite

Fragments of the shattered cores of early planetesimals: solid iron-nickel that cooled over millions of years, producing the interlocking Widmanstatten pattern revealed by etching.

Mohs 4-5 · Silver, Grey

Quartz

Pietersite

A brecciated chatoyant quartz in which fragments of tiger's eye and hawk's eye were shattered and recemented, producing swirling storm-like chatoyancy.

Mohs 6.5-7 · Blue, Gold

Sulfide

Pyrite

Iron sulfide that grows in astonishingly perfect cubes, dodecahedra and radiating suns. The Navajun mine in Spain produces cubes so sharp they look machined.

Mohs 6-6.5 · Brass, Gold

Beryl

Red Beryl

One of the rarest gem minerals in existence, found in commercial quantity at a single Utah locality. Manganese gives it a raspberry red no other beryl reaches, and faceted stones over a carat are counted in the low hundreds worldwide.

Mohs 7.5-8 · Red, Pink-red

Tourmaline

Rubellite Tourmaline

The deep red to hot magenta end of elbaite tourmaline. True rubellite holds its color under both daylight and lamplight rather than going brown, which is the trade's dividing line from ordinary pink tourmaline.

Mohs 7-7.5 · Pink-red, Magenta

Corundum

Ruby

Red corundum, colored by chromium, and the hardest gem material after diamond. Ruby in zoisite and ruby in fuchsite are the common specimen forms; gem crystals from Mogok are the historic ideal.

Mohs 9 · Red, Pink-red

Chalcedony

Sardonyx

Straight-banded chalcedony alternating reddish-brown sard with white — the classic cameo material, because a carver can cut through the pale layer to reveal the dark one beneath.

Mohs 6.5-7 · Red, White

Garnet

Spessartine Garnet

Manganese garnet in a vivid mandarin orange. Namibian material from the Kunene River gave the trade name 'mandarin garnet' in the 1990s; Chinese crystals from Fujian are collectors' pieces on smoky quartz matrix.

Mohs 7-7.5 · Orange, Amber

Feldspar

Sunstone

Feldspar with a glittering aventurescence from platelets of copper or hematite. Oregon sunstone is unusual in being colored by native copper, producing transparent red and green gems.

Mohs 6-6.5 · Orange, Red

Quartz

Tiger's Eye

Quartz that replaced fibrous crocidolite, inheriting its parallel structure and producing a rolling band of light called chatoyancy. Blue hawk's eye is the unoxidised form.

Mohs 6.5-7 · Gold, Brown

Silicate

Topaz

A very hard silicate that grows in glassy prismatic crystals. Imperial topaz, the sherry-orange to pink material from Ouro Preto, is the aristocrat of the family.

Mohs 8 · Colorless, Blue

Zoisite

Zoisite (Ruby in Zoisite)

Green zoisite studded with red ruby crystals and black hornblende, sometimes called anyolite. Bold, opaque and excellent for large carvings.

Mohs 6-7 · Green, Pink

Please noteTraditional properties, effects, and aura associations are shared for cultural, historical, and personal-interest reasons only. They are folklore, not medicine. Nothing here is medical, psychological, or financial advice, and no stone is intended to diagnose, treat, cure, or prevent any condition. Please see a qualified professional for health concerns.