Ruby (Corundum)

Ruby is the most popular gemstone variety in the Corundum family. The others are known as Sapphires. The word Ruby is derived from the color red. It is ideal to be used in jewelry settings. Rubies may be any shade of red. Their color ranges from pinkish to purplish to brownish red. Its color is dependent on the chromium and iron content of the stone. Frequent twinning of the crystals makes the material liable to fracture. Still, Ruby is one tough stone whose hardness is second only to diamond. Its crystal prisms are hexagonal with tapering or flat ends. As the crystals grow, they form new layers, depending on the geological conditions and minerals present. It even displays color variation, i.e., zoning.

Ruby is found throughout the world in igneous and metamorphic rocks. It is also seen as waterworn pebbles in alluvial deposits. Burma is the source of the most popular rubies in the world. Thailand produces rubies that are brownish-red. Besides, Pakistan, Afghanistan, Mozambique, and Vietnam have bright red stones. On the other hand, rubies from India, Norway, Russia, Australia, and North Carolina (USA) produce dark or opaque gemstones.

Mixed-cut is the most popular cut in Rubies. It is common to find rubies that are badly cut to retain the maximum weight of the gem.

Table of Contents

Ruby Color Zoning

It is essential to note that color zoning indicates the layers of growth in a crystal. They can be seen as a series of hexagons, which appear parallel to the prismatic crystal faces.

Star Cabochon Ruby

Star cabochon ruby can but cut when there are rutile inclusions present in the rough ruby crystal.

Synthetic Ruby

In 1902, a Frenchman named Augustus Verneuil produced a synthetic ruby crystal by exposing powdered aluminum oxide and coloring material to the flame of a blowtorch.