*Main countries where rubies are mined: Afghanistan, Cambodia, India, Kenya, Madagascar, Mozambique, Myanmar (Burma), Pakistan, Sri Lanka (Ceylon), Tajikistan, Tanzania, Thailand (Siam), Vietnam.
*Main countries where sapphires are mined: Australia, Cambodia, India (Kashmir), Madagascar, Myanmar (Burma), Nigeria, Pakistan, Tanzania, Thailand (Siam), Sri Lanka (Ceylon), USA (Montana).
Ruby & Sapphire Guide
The quality and value of a ruby / sapphire depend on a combination of the following criteria:
Carat weight
Weight of a ruby / sapphire is measured in carats. 1 carats = 0.2 grams. The heavier and the larger the ruby / sapphire usually the more rare it is.
Cut
Cut refers to the accuracy of the angles, proportions, symmetry and polish of the ruby / sapphire. It greatly affects how light travels within the ruby/ sapphire, and how it exits in the form of brilliance.
Color
Color is a matter of personal preference. Rubies vary in color depending mainly upon their chromium and iron content, whereas sapphires vary in color depending mainly upon their titanium and iron content, therefore ruby / sapphire from different countries* and mines have different predominant color
Rubies: Primarily red, range from brownish and purplish shades to orangish and pinkish ones.
Sapphires: Primarily blue, range from dark and purplish shades to greenish and yellowish ones.
But a natural color of ruby / sapphire will always have a greater value than an equivalent color obtained by heating or other processes.
Clarity
The clarity of a ruby / sapphire is determined by the number, size and location of inclusions which are natural materials present in the stone. They reflect its fascinating geological aspects, internally and externally too, there may be the presence of fissures, fracture and cavities which affect clarity.
Transparency
Transparency refers to the ability of a ruby / sapphire to transmit light. It is affected by the quantity or absence of opacity and brilliance present in the stone.
Gemstone Modification
Besides cutting and polishing, rubies / sapphires are commonly modified to improve their color and clarity. It is required that customers be informed about such modifications.
Ask for a written confirmation. The correct nomenclature of modified gemstones can be found in the CIBJO Gemstone Book.
Value of Gemstone
Moreover, the value of a gemstone is also defined by the combination of relative beauty, rarity and durability. Synthetic and imitation stones can be produced in industrial plants in any quantity and are therefore not rare and not considered precious. As a result, they cost much less than their natural counterparts of equal characteristics.
