Sapphire blue gemstone

Blue sapphire is a variety of corundum, one of the hardest minerals on Earth, valued for its intense color and durability.

About this subject

Blue sapphire belongs to the corundum family (aluminum oxide), the same mineral that forms ruby. Its characteristic blue color results from traces of titanium and iron in the crystal structure. With a hardness of 9 on the Mohs scale, second only to diamond, it is ideal for everyday jewelry such as engagement rings.

The most famous blue sapphire deposits are in Kashmir, Myanmar, and Sri Lanka. Kashmir sapphires, mined in the Indian Himalayas until the early 20th century, are considered the gold standard for a velvety blue hue. Sri Lankan sapphires, called Ceylon sapphires, display lighter tones and exceptional brilliance. Other important sources include Madagascar, Australia, and Thailand.

Historically, blue sapphire symbolized wisdom, nobility, and divine protection. European kings and queens used it in crowns and scepters. Princess Diana's engagement ring, now worn by Kate Middleton, features a blue sapphire surrounded by diamonds, further popularizing the gem. In astrology, blue sapphire is the September birthstone and associated with the sign of Virgo.

Heat treatment is common to improve color and clarity, and is accepted by the market when disclosed. Untreated natural sapphires with exceptional colors are extremely rare and expensive, sometimes fetching over US$ 10,000 per carat at auctions.

Frequently Asked Questions

What determines the blue color of sapphire?

The blue color comes from traces of titanium and iron in the corundum structure. This combination absorbs yellow and orange light, reflecting blue.

Which blue sapphire is the most valuable?

Kashmir sapphires, with their deep velvety blue, are the most prized. High-quality Ceylon sapphires also fetch high prices.

Do heat-treated sapphires lose value?

Heat treatment is widely accepted and does not devalue the gem as long as it is disclosed. Untreated sapphires are rarer and thus more expensive.