Gem-quality rubies are significantly rarer than diamonds, though there are certain types of diamonds that are very rare too. If you have ever walked through a jewelry store, or even the famed diamond district of New York City, most of the gems on display will be diamonds. Aside from their popularity in the gem trade, this is also attributed to their comparably low rarity.
For any crystal to be referred to as a type of gem they must be rare, durable, and beautiful.
R12576 | play | medium | left | “Ruby ID: R12576 – Weight: 1.57ct – Origin: Mozambique”The overwhelming presence of diamonds highlights the rarity of rubies on the market. Rubies that have evenly distributed color, high clarity, and rich saturation are highly sought after, making them incredibly expensive according to the 4Cs of color, clarity, cut, and carat weight.
Due to this rarity, people will compromise on certain aspects like carat weight, clarity, or factors outside the 4Cs (like treatments) depending on what they want and can afford.
The vast majority of rubies on the market are treated in some form or another, leaving the untreated material to be far rarer.
Diamonds are generally broken down into four groups: Type IA, IB, IIA, IIB. Of all the diamonds that exist, much less put on display, a majority are type IA diamonds. Being a type IA means in addition to the carbon that forms a diamond’s basic structure, there is a little bit of nitrogen fitted in that can make diamonds undesirably yellow. This accounts for 98% of ALL diamonds. The remaining 2% of diamonds are usually very unique, rare, and insanely expensive before any consideration of quality. This is also the percentage of diamonds that might show “fancy” colors, with few peculiar exceptions.
Some of the most spectacular examples of fancy color diamonds:
The 4Cs mentioned above also apply to diamonds, though they are balanced differently. For clarity diamonds are graded with 10x magnification, while rubies are graded without. Color is weighted more heavily for rubies, and in diamonds the 4C’s are weighted equally.
There is an exemption to these rules in diamonds for color, the “fancy” colored diamonds. Their 4Cs are graded more like rubies, with most of the emphasis on color. These make up less than the 2% margin of unusual diamonds, and are priced accordingly.
When comparing diamonds and rubies in general terms, rubies are much rarer than diamonds. If we weigh the most spectacular examples of each against one another, fancy diamonds are even rarer. However, fancy diamonds only make up a very limited market and are not available to most people, the same being true for the most spectacular examples of rubies. The value of color in fancy diamonds is extremely limited, and other gems usually show color better too. This is part of the reason we have namesake colors like ruby red and sapphire blue.