Blue crystals

Blue crystals get their colour from trace metals and light-scattering defects rather than from one shared mineral: 45 different stones read blue here, Amazonite, Amber and Angelite among them. Colour is the least reliable way to name a stone, so every entry carries the test that settles it.

• Amazonite6-6.5 Mohs · feldspar · heart, throatGreen microcline, coloured by trace lead and structural water, and named after a river it has never actually been found in. The Pikes Peak …
• Amber2-2.5 Mohs · organic · solar-plexus, sacralTree resin from Eocene forests, polymerised over 30 to 90 million years, and the only gem material that regularly contains a dead animal. T…
• Angelite3.5 Mohs · sulfate · throat, third-eye, crownAnhydrite, calcium sulfate with the water taken out, in a soft periwinkle from Peru, given a marketing name in the 1980s and now permanentl…
• Aquamarine7.5-8 Mohs · silicate · throat, heartBlue beryl, the same species as emerald with iron instead of chromium, and the traditional talisman of sailors, the Romans considered it Ne…
• Aragonite3.5-4 Mohs · carbonate · root, sacral, solar-plexusCalcium carbonate crystallised in the orthorhombic system instead of the trigonal one, which is the only difference between it and calcite …
• Aura Quartz7 Mohs · quartz · crown, third-eye, throatOrdinary quartz run through a vacuum chamber and fused with vaporised metal, a 1980s lapidary trick that produced the most photogenic objec…
• Azurite3.5-4 Mohs · carbonate · third-eye, throatThe blue copper carbonate, ground for centuries into the pigment that turned green in Renaissance paintings because azurite slowly becomes …
• Bismuth2-2.5 Mohs · man-made · crown, third-eyeElemental bismuth, grown in a saucepan and cooled slowly enough that the edges outrun the faces and produce those stepped rainbow labyrinth…
• Black Kyanite4.5-7 Mohs · silicate · root, throatIron-darkened kyanite from Brazil, growing in splayed fans that the trade decided look like a witch's besom and priced accordingly. It beha…
• Black Tourmaline7-7.5 Mohs · silicate · rootIron-rich tourmaline, common as gravel in pegmatite country, and the single most-recommended protective stone in the modern trade. It is ge…
• Blue Apatite5 Mohs · phosphate · throat, third-eyeThe mineral your teeth and bones are made of, and the Mohs scale's definition of hardness 5. Its name comes from the Greek for 'to deceive'…
• Blue Goldstone5-6 Mohs · man-made · third-eye, crownCobalt glass with copper crystals suspended in it, sold under a truly excellent name and a truly bad one, 'galaxy stone' is honest poetry, …
• Blue Kyanite4.5-7 Mohs · silicate · throat, third-eyeAn aluminium silicate that forms only at high pressure deep in the crust, so its presence in a rock tells a geologist how far down it has b…
• Blue Lace Agate6.5-7 Mohs · chalcedony · throatChalcedony banded in pale blue and white, essentially all of it from one region of Namibia, which is why the supply is finite and the price…
• Calcite (Coloured Varieties)3 Mohs · carbonate · sacral, solar-plexus, heartThe most abundant carbonate on earth in its decorative dress, orange and honey from Mexico, mint green from Pakistan, blue from Madagascar,…
• Celestite3-3.5 Mohs · sulfate · throat, third-eye, crownStrontium sulfate, the mineral that makes fireworks red, growing as pale blue crystal-lined cavities in Madagascan and Ohioan sedimentary r…
• Chrysocolla2.5-7 Mohs · silicate · throat, heartA hydrated copper silicate with no fixed hardness, ranging from chalk to gem depending on how much silica got into it. The Greeks named it …
• Emerald7.5-8 Mohs · silicate · heartBeryl coloured by chromium, and one of the four traditional precious stones, mined at Cleopatra's Egyptian workings, then in vast quantity …
• Fire Agate6.5-7 Mohs · chalcedony · root, sacralChalcedony that grew in stacked layers alternating with films of iron oxide only nanometres thick, so light interferes with itself and the …
• Fluorite4 Mohs · halide · third-eye, throat, heartCalcium fluoride in cubes and octahedra, coloured every shade in the box by lattice defects and trace elements, and the mineral that gave f…
• Galena2.5-2.75 Mohs · sulfide · rootLead sulfide in perfect silver cubes, the principal ore of lead, the source of Roman plumbing, Egyptian kohl and a great deal of historical…
• Green Aventurine6.5-7 Mohs · quartz · heartA quartzite glittering with chromium mica, mined chiefly in southern India and sold in more starter kits than almost anything else. The nam…
• Howlite3.5 Mohs · silicate · crown, third-eyeA calcium borosilicate from Nova Scotia that would be an obscure collector's mineral if it were not the perfect blank canvas, porous, white…
• Iolite7-7.5 Mohs · silicate · third-eye, throatCordierite, transparent and violet-blue, and famous for a story that may well be true: thin slices act as a polarising filter, and there is…
• Jadeite Jade6-7 Mohs · silicate · heartThe other jade, a sodium aluminium pyroxene, rarer than nephrite and the material of the Qing imperial court and Mesoamerican Olmec and May…
• Labradorite6-6.5 Mohs · feldspar · third-eye, throat, crownA grey plagioclase feldspar whose internal layering is spaced at exactly the wavelength of visible light, so it throws aurora colours from …
• Lapis Lazuli5-6 Mohs · rock (aggregate) · third-eye, throatA rock rather than a mineral, and one that has been mined at Sar-e-Sang in Badakhshan for over six thousand years, the same valley supplied…
• Larimar4.5-5 Mohs · silicate · throat, heartBlue pectolite from a single volcanic outcrop in Barahona Province, Dominican Republic, one mountainside, one country, no substitutes. It w…
• Magnesite3.5-4.5 Mohs · carbonate · crown, heartMagnesium carbonate, mostly an industrial refractory mineral, and the second great blank canvas of the crystal trade. Where howlite has bla…
• Moldavite5.5-7 Mohs · volcanic glass · heart, third-eye, crownGlass formed roughly 14.7 million years ago when an asteroid hit what is now Nördlingen in Bavaria, throwing molten terrestrial rock 400 ki…
• Moonstone6-6.5 Mohs · feldspar · sacral, third-eye, crownPotassium feldspar that unmixed into microscopically thin alternating layers as it cooled, scattering light into a floating blue-white glow…
• Nuummite5.5-6 Mohs · rock (aggregate) · root, third-eyeAn amphibole rock from Nuuk, Greenland, first collected in 1810 and roughly three billion years old, among the oldest material anyone sells…
• Ocean Jasper6.5-7 Mohs · chalcedony · heart, throatNot really a jasper: an orbicular rhyolite from the north-west Madagascan coast in which silica-rich fluids grew spherulites and then repla…
• Opalite5.5-6 Mohs · man-made · crown, third-eyeGlass. Not opal, not moonstone, not a mineral of any kind, an opalescent art glass produced in quantity and sold under a name engineered to…
• Picture Jasper6.5-7 Mohs · chalcedony · root, third-eyeVolcanic ash and mud laid down in still water, compressed, silicified, and then sliced, so the desert scene you are looking at is an actual…
• Pietersite6.5-7 Mohs · quartz · third-eye, solar-plexusTiger's eye that was shattered by tectonics and healed back together at every angle at once, so the light in it looks like weather. Found i…
• Rainbow Moonstone6-6.5 Mohs · feldspar · third-eye, crown, sacralThe best-selling moonstone in the world is not moonstone: it is white labradorite from India and Madagascar, flashing blue by a different o…
• Rainbow Obsidian5-6 Mohs · volcanic glass · root, third-eyeBlack glass with layers of aligned nanoscale crystals inside it, spaced closely enough to interfere with light and throw a spectrum out of …
• Sodalite5.5-6 Mohs · silicate · throat, third-eyeA feldspathoid, mined in quantity in Ontario after a 1901 find was used to decorate Marlborough House for Princess Margaret of Connaught, h…
• Spectrolite6-6.5 Mohs · feldspar · third-eye, crownLabradorite that shows the whole spectrum rather than just the blue end, found in quantity at Ylämaa in south-eastern Finland after quarryi…
• Strawberry Quartz (Glass)5-6 Mohs · man-made · heartTwo entirely different things share this name: a scarce natural quartz with red iron-oxide platelets, and an enormous volume of manufacture…
• Synthetic Opal4.5-6.5 Mohs · man-made · crown, heartReal opal chemistry assembled by people, silica microspheres stacked into the same diffraction lattice nature builds, then consolidated, of…
• Tanzanite6-7 Mohs · silicate · third-eye, crown, throatFound in 1967 in a strip of ground about seven kilometres long in the Merelani Hills of Tanzania, and nowhere else on earth. Tiffany rename…
• Tiger's Eye6.5-7 Mohs · quartz · solar-plexus, rootBlue asbestos fibres replaced molecule by molecule with silica, keeping the fibrous alignment and gaining a hard glassy body, the sheen is …
• Turquoise5-6 Mohs · phosphate · throat, third-eyeA hydrated copper aluminium phosphate that has been mined in Sinai and Iran for over six thousand years and in the American Southwest for a…

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