Smoky quartz is known for its large well formed crystals. They're usually translucent to transparent.
It's common for smoky quartz crystals to be inclusion free.
The mineral's colour is produced when impurities of aluminium in surrounding rock reacts to radiation.
Colour can vary from a subtle brown to yellowish-brown to a shade so dark it almost looks black.
A considerable amount of smoky quartz being sold commercially is clear quartz that's been heated.
Natural smoky quartz fades when exposed to high temperatures.
Smoky quartz is one of only a few brown coloured crystals from which gemstones are cut.
SHUNGITE
