Copper is my favorite metal to work with mainly because it's very flexible and easy to shape and bend and cheap too, which makes it the best material to use in jewelry prototypes, and accessories or in making big pieces of jewelry without worrying about it's price and how to sell it. when it come to buying copper it's not defined by karats but it comes in different grades there's the imported copper and the factory or workshop leftovers, the difference between them is, the imported copper is more flexible and softer which makes it easier to deal with and shinier that gives better looks to products, on the other hand the leftover is stiff and not very smooth but some times it's nice to use specially if u want the tough rough look, beside the leftover copper usually doesn't have a uniform color which i find somehow funky and nice, but when it comes to jewelry making i prefer to use the firsthand as when in contact with the skin it’s smooth and soft.
Copper comes in varies forms such as sheets, wires, pipes and rods it usually comes in two colors yellow and red.
copper also comes in different thicknesses starting from approximately 0.2mm to 7 or 8 mm in sheets, approximately from 0.5mm to 8mm in wire, and approximately from 0.4mm to 15, 20 cm diameter in pipes and rods.