Rainbow calsilica colourful man-made stone introduced in 2002

Rhodochrosite mined in north east Argentina since the times of the Incas

Rhodonite often features black markings caused by manganese oxide

Pink variety of the mineral quartz. Individual crystals have never been found

Red corundum is ruby all others colours are classed as sapphire

Ruby zoisite a combination of red corundum and green zoisite