Black Tourmaline Crystal Pyramid

Black tourmaline is schorl - a sodium iron-rich member of the tourmaline group, one of the most complex borosilicate minerals known, its formula running to a dozen elements. Iron gives the deep black. Mohs 7–7.5, harder than quartz and durable.

Tourmaline grows in long crystals with a rounded-triangular cross-section, scored with fine grooves down their length - striations that often survive into the polished surface as faint parallel lines, a signature of the mineral.

Tourmaline is notably pyroelectric and piezoelectric: warmed or pressed, a crystal develops an electric charge along its length. Eighteenth-century Dutch traders knew it as aschentrekker, the ash-drawer, for the way a warmed crystal pulls up ash and dust.

Asked often

What are the fine lines on the faces?
Striations - lengthwise grooves that form as the tourmaline crystal grows. They often survive cutting and polishing as faint parallel lines, and are a signature of genuine tourmaline.

Is it really electric?
Tourmaline is pyroelectric and piezoelectric - warmed or squeezed, it develops a small electric charge along its length. Dutch traders called it the ash-drawer for pulling up ash when warm.

Is it hard-wearing?
Yes - Mohs 7–7.5, harder than quartz. It takes a crisp polish and is stable; spare the apex hard knocks.

How do I care for it?
Dust with a soft, dry cloth, or wipe with a barely damp one. Hard and stable; spare the apex hard knocks.

1. Set on a desk or shelf, apex up.
2. Look closely at the faces - the fine lengthwise striations of the crystal often survive the polish.
3. Dust with a soft, dry cloth; an occasional wipe with a barely damp one.
4. Hard-wearing at Mohs 7–7.5; spare the apex hard knocks.

Many traditions set a stone where they will see it each day; where it sits, and what it marks for you, is yours to decide.

A piece to set down and return to. Hard and stable at Mohs 7–7.5; dust it with a soft cloth, and spare the apex hard knocks.

• Stone: Black tourmaline · schorl
• Composition: Complex sodium-iron borosilicate
• Crystal system: Trigonal
• Hardness: Mohs 7–7.5
• Character: Deep black · lengthwise striations
• Treatment: None · untreated
• Form: Pyramid · four faces, cut and polished
• Origin: Brazil
• Care: Dust with a soft cloth · spare the apex

Tourmaline’s electrical character made it an instrument of early science: in the eighteenth century Dutch traders used warmed crystals to draw ash from their pipes, and natural philosophers studied the same effect to understand how heat and electricity relate. The mineral sat on the laboratory bench before it was common in the jewellery box.

The name comes from the Sinhalese turmali, a term Sri Lankan traders used for the mixed gem gravels - tourmaline arrived in Europe as a stone whose own name admitted it had once been mistaken for others. Across many cultures the dense black variety was carried as a steadying token, named here as what people believed.