Ruby is a red gemstone. It's colour is mainly through its chromium content. Ruby is a variety of the mineral corundum (aluminium oxide).
We have three sizes of rough ruby. The small is approximately 1.5-2.5cm across the widest points. The medium is approximately 2.5cm -3.5cm across the widest points and the large are taller and chunkier. They are mainly hexagonal but as they are rough, they do not form perfect hexagonal shapes. Some are deeper than others and slightly less regular.