The world’s largest star blue sapphire was found in Sri Lanka. What are sapphires? Do you want to know the science behind the world’s largest star blue sapphire?


Sri Lanka, which is called the “pearl of the Indian ocean” is a small, beautiful island located in the middle of the Indian ocean. It is a country that has more than 2500 years of written history and according to those Sri Lanka was well known for gems for over centuries. Recent news sources report that the largest star sapphire was found in a town called Rathnapura, the gem capital of Sri Lanka. Actually, Rathnapura means “the city of gems” in the Sinhalese language.

 The star sapphire cluster was found in the backyard of a gem trader a few months back and they haven’t made it to the public due to security reasons. But now it has been notified to the authorities and it is now in safe hands. The cluster is weighed around 510 kg (1124.36 pounds) and it contains nearly 2.5 million carats.

The world's largest star blue sapphire and science behind it
Image from BBC

What is a Sapphire and a star blue sapphire?

Sapphire is a highly valuable gemstone that is basically made up of aluminum oxide (Al2O3). And there could be other elements also such as Iron (Fe), Titanium (Ti), Chromium (Cr), Vanadium (V), and Magnesium (Mg).


Sapphires are mostly blue in color. But very rarely sapphires are found in yellow, orange, green, and purple colors also.  Sapphire is one of the three big brothers of gemstone jewelry. The other two are emeralds and ruby. Corundum is the main mineral group that includes in both sapphire and ruby. Colors and the locale make the difference. Red-colored ones are mostly known as ruby.

There are four natural sapphire species.

  • Blue Sapphire
  • Colored Sapphire
  • Padparadscha
  • Star Sapphire

The most commonly found sapphire species is the blue sapphire. Those sapphires are cut and polish for the jewelry industry. Padparadscha sapphire is an extremely rare sapphire species. This variety gets its high value because of its extremely rare color. It is basically a mix of pink and orange but most people say the actual color cannot be described by words. The name “Padparadscha” is a Sanskrit word that means “rich color of a lotus flower”.


The sapphire which was found in Sri Lanka is a star sapphire. It is also in the corundum category and the specialty is the natural reflection it gives is always looks like stars. The internal molecule structure is the key to this reflection. The number of the bands of the reflecting star is a factor for the value of the sapphire. Usually, they are 2,3, or 6 intersecting bands. Sapphires which have 12 rays are very rare and highly valuable.

Uses of Sapphires

You already know that sapphires are widely used as gemstones in the jewelry industry. But that is not the only use from the sapphires. Sapphires are made from natural elements highly compressed under the Earth’s crust for millions of years. Therefore the structure of sapphires is very strong. These are known as the third hardest mineral in the world which have 9 on the Mohs scale. Therefore, they are used in many ways.

They are used in infrared optical components, high durability windows, solid-state electronics such as integrated circuits, LEDs, and wristwatch crystals. Sometimes sapphires are made synthetically for those purposes since the value of the natural sapphires is very high.


Report inappropriate content