Properties of Blue Sapphire Gemstone

by Sehdev Jewellers Gemologist, Gemstone Dealers

There are many takers of beautiful gemstones around the world. With so many gorgeous gemstones offering several benefits to the users, it becomes understandable why their demand has increased over the years. One such gemstone that has been a favorite of many gemstones and jewelry lovers is the stunning Blue Sapphire.

Amazingly exquisite, the Neelam Stone has been winning hearts for centuries. The deep blue color of the stone attracts the onlookers at first sight.

For those who are intrigued by the stone and wish to know more about it, here is some important information about the chemical and physical properties of the Blue Sapphire gemstone.

Blue Sapphire Chemical Properties

Composition: The gorgeous Blue Sapphire gem is a variety of the mineral corundum and is made up of Aluminium Oxide (Al2O3).

Hardness: This gemstone is known for its durability and long life, thanks to its hardness of 9 on the Mohs scale.

Refractive Index: Blue Sapphire’s refractive index lies between 1.760-1.768 and 1.770-1.779.

Specific Gravity: The specific gravity of this gemstone ranges between 3.99 and 4.00

Blue Sapphire Physical Properties

Carat: Blue sapphire is measured in carat, and the size of the stone varies as it is extracted from forests and rocky regions. Being heavier in weight than most of the gems, a one-carat sapphire looks smaller than a diamond.

The more the size of the blue sapphire, the higher price it commands. However, only natural and genuine blue sapphires are expensive. Since large blue sapphire stones are rarely found, any blue sapphire gemstone that is above 15 carats having a great quality, becomes an exotic piece. A 536.35-carat star sapphire, the Star of India, is believed to be one of the largest gemstones in the world.

Cut: There are various types of cuts that can adorn a Blue Sapphire gemstone. From oval to prince, square, round and angel, the variety is huge. However, an oval-shaped blue sapphire stone is considered one of the best gemstones from the range.

A well-cut sapphire is symmetrical and reflects light at correct angles to increase the stone’s gleam. This gives the stone a darker color. But if the Neelam stone is very dark, then it might be given a shallow cut to produce more light within and give the stone a bit lighter tone. Natural blue star sapphires are usually given a cabochon cut to get the asterism effect.

Color: Color of any gemstone acts as a determining factor when it comes to ascertaining its worth. A Blue Sapphires may be available in a darker color or in a bit lighter shade. The color of a gemstone is based on its hue, saturation, and tone.

Blue sapphires get their magnificent color from the presence of trace elements iron and titanium. The richer the color blue, the expensive will be the stone. Such a sapphire may fall into the category of “cornflower blue,” which gets its name from the cornflower which is truly blue, rather than carrying a bit violet or purple shade.

Clarity: Just like any other gemstone, finding a natural blue sapphire without any inclusions or imperfections is highly unlikely. As a matter of fact, the absence of any inclusions may hint at the stone being an imitation. So, if you find a blue sapphire which is flawless and which seems unbelievably inexpensive, then it may be a synthetic blue sapphire.

One of the most common inclusions in a blue sapphire is rutile needles or silk. Color zoning is also a bit common, and you may also find crystals and feathers. Asterism or the star effect is a desirable inclusion in sapphire gemstones.