Various types of Quimbaya gold object, such as ornaments, lime-flasks, trumpets and helmets, featured human figures. Men and women are both represented, usually naked except for adornments such as necklace, earrings, diadem, nose ornaments and leg bands. Here a woman and a man stand back to back on the cylindrical socket.The Quimbaya used innovative metalworking techniques to produce outstanding pieces. They cast most objects not in pure gold but in an alloy of gold and copper, called tumbaga, which offers a great advantage in the casting process since it has a lower melting point than purer metals. Silver, also present in the alloy, occurs naturally in some gold deposits and was not added intentionally.However, the composition of the alloy may not have been chosen for its technical properties alone. Depending on the purity of gold or the amount of copper added, tumbaga shows a wide range of colour. The different hues obtained probably had symbolic values among the ancient cultures of present-day Colombia. Many of the coppery-coloured tumbaga castings were then gilded and burnished to restore their golden appearance. This process would also have helped to avoid superficial oxidation and corrosion, enhancing their durability.