Deep to light blue gemstones, sapphires are one of the ‘big four’, the four precious gemstones that are popularized in fine jewelry all over the globe. Coveted for their velvety appearance and stunning azure color, they often fetch a high price depending on factors such color, cut, clarity and carat size. In this blog, we will share with you everything you need to know about sapphires and their various types.
What are Sapphires?
Sapphires are predominantly blue gemstones that belong to the mineral group known as corundum. In its actual form, corundum is colorless and becomes sapphire upon having traces of a transition metal which lends it its coloration. Depending on which trace element it contains, sapphires might be differently colored. Unlike its red gemstone twin,rubies, which are colored by traces of chromium, sapphires may contain traces of iron, titanium, vanadium and chromium.
Technically, sapphires are one of the hardest gemstones with a Mohs scale rating of 9. This makes them a reliable gemstone to use in fine jewelry, fit for any kind of wear and tear due to being scratch resistant. A significant amount of the sapphires mined undergo heat treatment to improve their color and remove an effect known as color zoning. Color zoning happens when a sapphire consists of more than one trace element, leading to streaks of a different color, most commonly seen in blue, purple and yellow sapphires.
Historically, sapphires were often revered for their blue color. The word itself is derived from the Greek word sappheiros, as well as the Latin word ‘saphirus’, both of which translate to the word blue. Used by nobility since ancient times, sapphires were worn to ward off envy, worn by clergymen to denote heavenly favour and to signify faithfulness. Sapphires became a symbol of romance in the modern age when Princess Diana received an oval-cut Sapphire ring from Prince Charles on the occasion of their engagement. Since then, sapphires have been a most popular choice of stone to be used especially in wedding and engagement jewelry.
Types of Sapphires
As far as the coloration of these blue gemstones is concerned, the most sought after varieties are light, cornflower blue to the deep velvety undertones of Kashmir sapphires. Like rubies, blue sapphires have a special variety known as star sapphires. This variety exhibits an effect known as Asterism, where needle-like inclusions create a mesh that looks like a star. To enhance and highlight the effect, they are cut as cabochons.
Fancy sapphires are another variety which consist of a wide range of colors. Fancy sapphires include yellow, pink, orange, green, brown and purple to violet hued sapphires. These occur when the sapphires include different trace elements as mentioned earlier. There is also a colorless variety which is often used as an alternative to diamonds and often confused for white topaz.
An exemplary variety, Padparadscha sapphires have a beautiful salmon color. From the sanskrit word used to describe the lotus flower, their rarity and price are unmatched. While color zoning is not considered favourable for most fancy colored sapphires, in this case pink and yellow color zoning in sapphires might lead them to be labelled as the Padparadscha variant. Padparadscha sapphires are mostly found in Sri Lanka but some deposits have been found in Eastern Africa as well as Vietnam.
Another interesting phenomenon includes color change sapphires. These sapphires look different in color under different lighting. In natural light, they will look blue, and when they are viewed under indoor or incandescent light, they will be more purple hued. Similarly, green hued sapphires that look so in natural light will look red under incandescent light.
Most varieties of sapphire come from Australia, Kashmir, Myanmar, Afghanistan, Thailand, Columbia and many African countries. Reserves also found in China, USA and Vietnam. Some sapphire varieties belong to particular locations, such as Kashmir sapphire earrings.
A large number of sapphires in the market are subject to heat treatments, irradiation and diffusion treatments, with lattice diffusion treatment giving the most undesirable results. There are also many synthetic varieties including lab-grown sapphires, synthetic color change sapphires, doublets and glass. Natural substitutes to blue sapphires include blue spinels,kyanites, iolites and in some cases, amethysts.
While there has been an influx of synthetic gemstones and substitute stones for blue sapphires, some certified jewelry brands use only natural, handpicked specimens to use in their piece. At Galt and Bro we strive to provide natural, untreated and evenly saturated blue sapphires as part of our loose gemstones catalogue. We also offer customised services where you can pick a gem of your liking and have us create personalized jewelry according to your requirements. For more details visit https://galtandbro.com/personalized-creations/