Rarity of Rubies versus Diamonds
Gem-quality rubies are significantly rarer than diamonds, though there are certain types of diamonds that are very rare too. If we weigh the most spectacular examples of rubies and diamonds against one another, diamonds that show color are even rarer. In general terms however, just look at most jewelry counters. Nearly everything you see in the counters will be diamonds, to the point that finding other types of jewelry may require custom orders.
Ruby Rarity
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.
Diamond Rarity
Diamonds can be mined from just about anywhere in the world, so long as carbon is subjected to the correct pressure and temperature
Diamonds are generally broken down into four groups: Type IA, IB, IIA, IIB. Of all the diamonds that exist, 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.
As shown above, fancy colored diamonds are treated as an entirely different group of gems. The distinctions between colored and colorless diamonds gives insight to how appealing color is, even if the type of gem is not a diamond.
Fancy Colored Diamonds
Some of the most spectacular examples of fancy color diamonds:
Fancy color diamonds are also the most expensive type diamonds on the market. For example, the Hope Diamond has an impressive estimated minimum value of $200 million USD and maximum of $500 million. These proposed numbers are huge sums, but they are also representative of the value of a diamond that is a perfect sapphire blue. It is that much rarer than blue sapphires in nature.
4Cs Between Rubies, Diamonds, & Fancy 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.
4Cs Standards Rubies, Diamonds, & Fancy Color Diamonds
| Rubies | Diamonds | Fancy Color Diamonds | |
| Color | Vivid Red | No Color | Color |
| Clarity | Some Inclusions | Clear under 10x Magnification | Some Inclusions Under 10x |
| Cut | Somewhat Irregular | Perfect | Slightly Irregular |
| Carat Weight | Often < 1ct | Often a few carats | Often < 1ct |
Chart Notes
Color
Notice how rubies are listed with vivid red and not color? This is because rubies typically display the best possible color of red. Fancy colored diamonds usually only display pastel colors that are not very vivid, hence the absence of “Vivid”. They can show vivid color, but this is not expected.
Clarity
Diamonds are the only gem evaluated with 10x magnification. All other gems are graded based on what is eye-visible. Fancy color diamonds fall between the two because they are diamonds, but they are graded more like rubies.
Cut
Diamonds benefit from their cut by showing more sparkle and rainbow colors called fire. This is most visible when the diamond is colorless. Colored diamonds will still benefit from an ideal cut, but the color does muffle these visual effects, thus cut is not as strict in colored diamonds. Rubies do not benefit from an ideal cut the way diamonds do, and outside of calibrated sizes are never cut ideally.
Carat Weight
This is a judgement purely of rarity, and rubies do not like to grow large. Diamonds are much more inclined to grow to larger sizes. Fancy colored diamonds often grow much larger than rubies too, though are much scarcer, so finding them in any size is pretty amazing.
Above is a table for how these gems are typically judged. Rubies and diamonds are judged completely differently on all counts, including carat weight. Notice how differently fancy colored diamonds are judged differently from typical diamonds. This is because fancy diamonds are being judged less for perfection, and more for color like rubies are.