Quartzite - cabochon solid 40mm / 24mm - for macrame or mounting jewelry - size personal. Quartzite is so common that it is never cut, but a little patience, because it is very hard, sometimes delivers surprises. Here is one, you won't find anywhere else! Quartzite is a siliceous rock, made of welded quartz crystals. It has a broken congresses. Its color is usually clear.