|Malachite is most often found in massive forms with various patterns. It is often found in botryoidal masses that produce bulls-eye patterns when sliced through. The concentric circular patterns are very desirable in the final stones.
It is often found in association with azurite (a more complex copper carbonate). The azurite is dark blue and contrast well with the green malachite. The stone is very susceptible to acid as are most carbonates.
Some of the very best current material comes from the African Congo. The Congo regulates the export of the stone and will not allow the rough to be exported directly. Thick slabs of malachite are cut then impressed with a shallow circular depression and exported as ash trays. These eventually find their way into the US market and are sold by the pound for cutting material.
Rounded masses of polished malachite are also sold as sculpture and again are often purchased to recut.