Updated: Mar 27
Sapphires & Rubies: Precious Gemstones
Did you know sapphires and rubies are relative stones? Learning about sapphires and rubies opens up a world of vibrancy and color
What are Rubies & Sapphires?
Sapphires and rubies are precious and rare varieties of the mineral family corundum. Corundum is crystalline form of aluminum oxide (chemical formula Al2O3) and is a naturally occuring mineral found in metamorphic and igneous rocks. Certain amounts of trace elements affect the color of each variety.
Corundum is very hard and tough, rating 9 on the Mohs scale of hardness, a scale developed to reference minerals rating 1 through 10, determining the hardness of minerals or “scratch resistance.” Corundum is close to diamond (10) and moissanite (9.25), making rubies and sapphires very durable and perfect for wearing frequently.
Corundum has a high specific gravity of 4.00, resulting in a dense mineral due to its strong aluminum-oxygen bonds. Corundum has a refractive index of 1.76-1.78 with an adamantine to vitreous luster, adding to its distinctive appearance.
Sapphire & Ruby: A Rainbow of Luxury
According to GIA (Gemological Institute of America), the most valued blue sapphires display medium to medium dark tones of velvety blue to violetish blue. Kashmir, Ceylon, and royal blue sapphires are always in demand because of their incredibly beautiful blue shades.
Although sapphires are synonymous with blue, they come in a rainbow of shades, making them ultra-versatile for imaginative jewelry designs. Sapphires are readily available in colourless/clear, pink, orange, yellow, green, and purple, as well as unique mixtures of all of the above.
Sri Lankan Padparadscha sapphires are generally very expensive, displaying a pinkish-orange hue reminiscent of a sunset. Sapphires also exhibit chatoyancy and asterism characteristics due to oriental inclusions, such as star sapphire.
Rubies get their stunning red color from the trace element of chromium. The presence of chromium influences the shade of red, ranging from pinkish (almost like a pink sapphire) to deep red shades with purplish undertones referred to as “pigeon’s blood.”
The value of both sapphire and ruby depends on their hue, saturation, clarity, carat/size, and origin. Sri Lanka is known as the premier source of high-quality sapphires that are sought-after worldwide.