Notes from the Gallery

Emerald's mineral and aquamarine's mineral, coloured pink by manganese and named in 1911 for an American banker — and routinely confused with three other stones.

The common massive rose quartz and the rare crystallised kind are coloured by different things, and they behave in opposite ways in light. One trade name covers both.

Diaoyudaoite was approved as a mineral species in 1985 and sits on the official list today. The literature that studies it now says it is probably industrial waste. Both facts are true at once.

All fluorite shares one cubic lattice, yet it grows as cubes, octahedra and stranger things besides. The shape is set by the fluid it grew from, and one common shape may never have been grown at all.

Brazil's "garden quartz" seals a tiny landscape inside clear crystal. It is often sold as "phantom quartz" — but a garden and a phantom are two different things.

In 2020 a wave of electric-blue "Mexican hemimorphite" swept the mineral market. It was beautiful, it was convincing — and much of the colour had been added with industrial pigment.

The two most famous coloured gems in the world are one mineral wearing two names — and the difference between them comes down to a handful of stray atoms.

Every tanzanite on Earth comes from a single hillside in Tanzania — and inside each crystal are three different colours at once, depending on the angle you look through.

The golden quartz hides a quiet disagreement between mineralogists and the gem trade — and knowing which "citrine" you're holding changes what you've actually bought.

A rare Colombian emerald grows a six-spoked wheel of dark carbon inside the green — a pattern that records the exact moment its own growth was interrupted.

The giant violet cathedrals begin as nothing at all — an empty pocket swelling inside altered volcanic rock, then filled drop by drop. The leading explanation is stranger than the textbook one.