The ruby is a variety of corundum and derives its name from the Latin ‘rubeus’, meaning red. The term ruby first appeared only in the Late Middle Ages. Before that the stone was known in Italian as “carbonchio”, small piece of coal, on account of its colour, reminiscent of burning embers. Its typical inclusions are very fine rutile needles that intersect to form a lattice known as ‘silk’.
When this lattice is extremely close-knit, reflecting the light it may form a distinctive six-pointed star, in which case we call it a ‘star ruby’.
The rarest, reddest rubies come from Burma. Those from Thailand are darker, while those from Sri Lanka are pinkish in colour. Other good quality rubies come from Africa and Madagascar.