Gemology 101: Star Sapphires

Gemology 101: Star Sapphires

You know sapphires — but what about star sapphires? Here’s a quick hit of everything you need to know about this unique gemstone.

What is a Star Sapphire?

Star sapphires are a type of sapphire that feature a star-like appearance known as an asterism, a word derived from the Latin “astrum,” which means “star.” While technically this asterism is an inclusion — so a flaw in the gemstone — this is one instance where a flaw is desirable. The star effect lends the gemstone an otherworldly appearance, as running lines across the sapphire’s body reflect light and form a four, six or 12-rayed star.

Other gemstones that sometimes feature asterisms include rubies, moonstones and rose quartz. In sapphires specifically, asterisms can occur in any color sapphire, though asterisms are least common in yellow, orange and green sapphires.

While star sapphires aren’t as well known as traditional sapphires, they were quite popular during the Golden Age of Hollywood and some of the largest sapphires in history have been star sapphires. Recently, star sapphires have gained new interest, especially as designers and jewelry collectors alike turn their attentions to raw, natural stones and nature-inspired designs.

Gemology 101: Star Sapphires

While star sapphires aren’t as well known as traditional sapphires, they were quite popular during the Golden Age of Hollywood and some of the largest sapphires in history have been star sapphires. Recently, star sapphires have gained new interest, especially as designers and jewelry collectors alike turn their attentions to raw, natural stones and nature-inspired designs.

 

A perfect star sapphire will feature a perfectly-centered star (when viewed from above) and each of the star’s rays, or legs, should be equal in length. Each star ray should be clearly defined and not fuzzy, and should reach all the way to the stone’s base without any gaps. Ideally, the rays should not impact the clarity of the overall sapphire. 

But note — while this is what a perfect star sapphire looks like, this level of perfection is exceedingly rare, so any “perfect” star sapphire should be considered with some degree of caution.

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