What's the difference between Pink Sapphire and Rich Red Ruby?

Did you know that Ruby and Pink Sapphire are both variations of the same mineral - corundum (the technical term for sapphire)? Read on to find out what is the difference.

 

From a scientific standpoint, rubies and sapphires are variations of corundum, a crystalline form of aluminum oxide (Al2O3), which obtains its distinctive colors from impurities or trace elements like iron, titanium, or chromium. These impurities produce a spectrum of hues within corundum crystals, encompassing shades such as gray, brown, yellow, green, blue, purple, red, and pink.

So, what distinguishes rubies from pink sapphires?

Well, there's an old joke that claims the answer depends on whether you're the buyer or the seller. In reality, there isn't a universally agreed-upon distinction, but it all revolves around the color pink. Let's delve into the definition of rubies and sapphires:

 

Ruby is specifically defined as red corundum, with chromium being the primary contributor to the red coloration in corundum gemstones. Any other corundum varieties that aren't red fall under the classification of sapphire. (Sapphires can contain a mixture of chromium, titanium, and iron traces.) While sapphires are commonly associated with blue, they encompass all non-red colored corundum gems. It's no surprise, then, that pink marks the boundary between rubies and sapphires since pink is often regarded as a lighter shade of red.

Describing color involves both objective and subjective elements. Color can be quantified scientifically in terms of hue, tone (lightness), and saturation (intensity). Recent advances in colorimeters have addressed unique challenges posed by the optical qualities of gemstones, such as pleochroism and transparency.

 

So, why is there no consensus on the distinction between rubies and pink sapphires? The issue primarily boils down to subjectivity in naming specific sets of color measurements. It's rooted in cultural and historical factors, asking the question: What exactly is pink? Richard Hughes, in a fascinating article, notes that prior to the 20th century, pink was considered a "light red," and some rubies were even described as "pink rubies." But during the 20th century, someone decided that pink was distinct from red, leading to the emergence of the term "pink sapphires."

Professional gemology associations vary in their approach to differentiating rubies from pink sapphires. The Gemological Institute of America (GIA) acknowledges historical and cultural variations in the division (or lack thereof) between red and pink colors. They classify as rubies only those corundum gems with a "dominant" red hue, designating all other corundum as sapphire. 

 

In contrast, the International Colored Gemstone Association (ICA) considers any red corundum gemstone, regardless of depth or intensity, to be a ruby.

The International Gem Society (IGS) acknowledges the lack of a general consensus on the distinction between rubies and pink sapphires and provides information on both "pinkish" rubies and pink sapphires.

 

Could the growing demand for pink sapphires alter how we distinguish these gems? Throughout history, sapphires have been highly valued in jewelry. However, the demand for "blood red" rubies has always been exceptional, as gem-quality rubies are rarer than diamonds. This desire has driven the need for a strict definition of rubies, potentially contributing to the rise of the "pink sapphire" category, as sellers might prefer to market their gems as rubies.

Nonetheless, there has been a recent increase in consumer demand for pink sapphires, challenging the notion that pink and red were ever considered the same color. According to David Federman, "Today, pink sapphire needs no favors or apologies," and "hot pink" sapphires are in demand. Whether this rising demand for pink gems will reshape the boundary between rubies and pink sapphires remains to be seen and will likely depend on market dynamics over time.

Want to learn more? Book your appointment to view the Ruby and Pink Sapphire collection at DesignYard.