Today's Colour and Stone

The twenty-four stones in this deck

Every stone the deck can draw, with what it is made of, how hard it is, where it comes from, and the material most often sold in its place. Drawing a card picks one of these; the whole list is here so you do not have to draw to look one up.

Where a check for one of these imitations stops working is written out in the guides.

Why each of them looks the way it does

• Amethyst — The purple comes from traces of iron in the lattice, plus a long spell of natural radiation underground. The name is from the Greek amethystos, meaning “not drunk”.
• Citrine — The name comes from the French citron, lemon. Natural citrine is scarce — most citrine sold is amethyst that turned yellow under heat.
• Rose Quartz — The pink is not dye. Inside the stone is a layer of mineral fibres too fine to see, and light scatters as it passes through.
• Clear Quartz — The word quartz entered English later than most gem names, from German miners' slang. It is one of the commonest minerals in the crust.
• Smoky Quartz — An aluminium-bearing lattice turns this colour under natural radiation underground. The Cairngorm mountains in Scotland are its most famous source, and there it is called simply by the name of the range.
• Rutilated Quartz — Those hairs are rutile, a second mineral grown inside the quartz. Natural rutile needles are straight and stiff, and often cross one another at sixty degrees.
• Garden Quartz — That little mountain inside is chlorite that settled on the surface while the crystal paused growing, and was then sealed in by new quartz.
• Ametrine — The temperature was uneven inside one crystal, so half of it changed colour and half did not. Natural sources are very few; almost all of it comes from a single Bolivian mine.
• Garnet — Garnet is not one stone but a whole family, its members running from red to green. The name is from the Latin granatum, pomegranate.
• Aquamarine — It is the same mineral as emerald; the difference is only which elements got mixed in. The name is from the Latin aqua marina, sea water.
• Morganite — The colour comes from traces of manganese. It is named after the early twentieth-century collector J. P. Morgan, one of very few gems named after a person.
• Labradorite — That blue is not a colour. It is light interfering between extremely thin layers. The name comes straight from Labrador, where it was found.
• Moonstone — Two feldspars grew together inside it in very thin layers. Light scatters between them, and only then does the sheen appear that follows your eye.
• Amazonite — The colour comes from traces of lead. The white grid on the surface is the mark of two feldspars grown together, and it is the easiest way to recognise it.
• Fluorite — Only 4 on the Mohs scale — a nail clipper will scratch it. The name is from the Latin fluere, to flow, because smelters used it as a flux.
• Malachite — The green comes from copper; it is a copper ore in its own right. The concentric bands were laid down one at a time, each one a separate episode of crystallisation.
• Lapis Lazuli — The gold specks in it are pyrite, not gold. The name reached European languages through the Persian lazaward, and the word azure came from it too.
• Tourmaline — Strong lengthwise striations on the prism faces and a rounded triangular cross-section — those two things identify it. The name comes from the Sinhalese turmali.
• Obsidian — It is glass; the difference is that a volcano made it. The lava cooled too fast to crystallise, which is why it breaks in shell-shaped curves.
• Tiger's Eye — The moving band of light is a reflection off aligned fibres; it has nothing to do with cats. Quartz and crocidolite fibres grew alternately into the same crack.
• Kyanite — The same stone can be scratched along its length but not across it. Hardness that changes with direction is almost unique among common gems.
• Calcite — Put clear calcite over a line of print and the line becomes two. It is the classic teaching example of double refraction — quartz doubles too weakly for the eye to catch.
• Aventurine — The green comes from platy chromium mica inside it, which is also why it glitters. It is a quartzite, not jade, and not a single crystal.
• Sunstone — What glitters inside are extremely thin platelets of hematite; when they all line up the whole stone lights at once.