The September Birthstone: Sapphire, The Origin Story

Sep 17, 2020 | Birthstones, Sapphire

Art Deco Sapphire & Diamond Engagement Ring in Platinum

This piece has an intricate filigree mounting with milgrained wire work and curved open spaces around the diamond accents. The domed contour gives this ring a large ornate look that could easily be worn as a cocktail ring.

Oval Sapphire & Diamond Engagement Ring 18k White Gold

This oval has a rich, dark blue color that contrasts well with the white gold and vibrant diamond that flank it’s sides it. The large bezel facets and four prong mounting give lovely flashes and allow for more shades of blue to appear.

The sapphire has been a popular gemstone for thousands of years. The Greeks gave it the name sappheiros which likely referred to Lapis Lazuli. Given that the name refers to a very blue stone, it is important to note that sapphires come in many more colors than just blue. We mentioned in our blog about rubies that both stones are made of an aluminum oxide called corundum. Gem quality corundum of any color other than red is considered sapphire, while red is considered ruby.

Gemstone treatment

Heat treatment of sapphires (and many other gems) is a common way to improve color and clarity. Pure corundum is naturally colorless, and these stones get their color from impurities like iron, titanium, and chromium. Stones with iron and titanium will present the beautiful blue hues that are synonymous with the sapphire. There are many processes sapphires are put through to alter specific parts of the gemstone. For instance, when you apply very high heat to a sapphire that contains the right amount of titanium and iron oxides(in an environment of hydrogen), and then cool it at the correct rate you will greatly increase the saturation of blue.

Processes like this can be done to remove “silk”, add silk/increase the amount to enhance a star sapphire, and even to lighten the color of a blue sapphire.

Sapphires on the hardness scale

Corundum is the second hardest naturally occurring gemstone (unless you count Moissanite, and while you’d be technically correct…you’d be a pedantic petrology dork) which makes it perfect for jewelry!

Star Sapphire

Sapphires with rare six pointed asterisms are called star sapphires. These can occur in many different colors, but white inside dark blue is probably the most well known. These stones are usually cabochon cut with a high dome to enhance the display of the star.

Learn more about the history and lore of sapphires!