Ruby is a variety of corundum, like sapphire. It owes its name to its red color (Latin "Rubeus"). He was attached to the corundum group around 1800. Prior to this, he was associated with "carbuncles" with pyrope garnet and red spinel. The red color is not the same for all the rubies of the same deposit. The most sought after of all colors is called "pigeon blood" red hardwood with a hint of blue. The color is attributed to the presence of chromium. Rubies and sapphires are the hardest mineral after diamond. The inclusions are very common. They do not determine the quality of the gem; they guarantee the authenticity of natural versus synthetic ruby ​​ruby. The nature of inclusions provides many indications of the type of deposit. The largest holdings are in Burma, Thailand (Siam), Ceylon and Tanzania. Other deposits exist in Afghanistan, Mozambique or Madagascar ... Ruby is one of the most expensive gems. Large ruby ​​gems are rarer than diamonds of the same size. Ruby is a classic jewelry: rings, earrings, necklaces, but it is also found on the crowns of the most prestigious collections.