(Gemstones)
Gemstones
Four stones and a hundred years of knowing where to find the best of them.
01 / 04 · Mohs hardness 10 · refractive index 2.42
Diamond
Carbon, crystallised 150 km down and three billion years ago.
02 / 04 · Mohs hardness 7.5 · refractive index 1.58
Emerald
Beryl coloured by chromium. Its garden of inclusions is its signature.
03 / 04 · Mohs hardness 9 · refractive index 1.77
Sapphire
Corundum coloured by iron and titanium, every blue from sky to ink.
04 / 04 · Mohs hardness 9 · refractive index 1.77
Ruby
Corundum coloured by chromium. Above 3 carats, rarer than diamond.
