Scapolite is a lesser-known aluminosilicate that deserves more attention. It is actually a mineral series running between sodium-rich marialite and calcium-rich meionite, and gem stones come in honey yellow, pink, violet and colourless. Some stones show a lovely cat's-eye when cut as cabochons, and many fluoresce dramatically under UV light. The name comes from the Greek for rod, after its columnar crystals. Fine gems come from Tanzania, Madagascar, Myanmar and Afghanistan. Its violet stones can pass for amethyst, and the yellows for citrine, until you test them.
Scapolite sits at 5.5 to 6 on the Mohs scale with cleavage, so it is more of a collector's and occasional-wear gem than a daily ring stone. Earrings and pendants suit it well. Clean stones are faceted, while fibrous material becomes cat's-eye cabochons. Keep it away from knocks, ultrasonic cleaners and harsh chemicals, and wash it gently in lukewarm, soapy water. Its rarity in mainstream shops is exactly what makes it fun to own.
Obsidian shares its jet black colour, while a deep-blue iolite can have a similar look.
