When evaluating any type of gem, rarity plays a direct role in determining the value of the stone. In the case of rubies, this rarity is not just marketing—it’s geological. Gem-quality rubies with vivid color, minimal inclusions, and over one carat in size are exceptionally scarce.
Compared to diamonds, even those that show color, rubies are rarer and harder to find in natural, untreated form. That scarcity, especially for stones visible to the naked eye with strong color, is what gives ruby gemstones their status among collectors, investors, and buyers of high-end ruby jewelry.
How Rare Are Rubies?
Rubies are among the rarest gemstones in the world—rarer than diamonds, especially when considering untreated, gem-quality stones over one carat.
Unlike diamonds, which are mined in large quantities across multiple continents, rubies form under very specific geological conditions that limit both size and clarity.
According to data from the GIA, over 90% of rubies on the market are heat-treated to enhance color or reduce inclusions.
Untreated rubies with strong red color and eye-clean clarity represent less than 1% of global ruby supply. Larger sizes are even harder to find—a fine, untreated 2-carat ruby is rarer than a 5-carat D-color diamond.
In 2015, the Sunrise Ruby, a 25.59-carat untreated Burmese stone, sold at Sotheby’s for $30.3 million, setting a record for any colored gemstone at $1.18 million per carat. That sale highlights just how scarce high-quality rubies are in the global market.
Natural vs. Synthetic Rubies: Which Are Truly Rare?
To answer this, we must separate lab-grown rubies from those formed in nature.
| Feature | Natural Ruby | Synthetic Ruby |
|---|---|---|
| Formation | Millions of years in Earth’s crust | Weeks in a laboratory |
| Rarity | Extremely rare | Not rare |
| Inclusions | Present (natural markers) | Often flawless |
| Price per carat | High (especially untreated, vivid color) | Low |
| Investment value | High (collectible asset) | Low |
Synthetic rubies look similar to rubies but lack the natural formation process and scarcity. They’re not fake, but they aren’t rare.
What Makes a Ruby Rare?
Several factors contribute to the rarity of ruby gemstones, especially when compared to more abundant stones like diamonds or sapphires.
1. Stone’s Color
Color is the single most important factor. Red rubies with strong saturation and little secondary tone are the most valuable.
The ideal color is a vivid red to slightly purplish red. If it leans too pink, it’s classified as a pink sapphire.
| Hue | Classification | Market Value |
|---|---|---|
| Vivid red | Fine ruby | Highest |
| Slightly purplish red | Acceptable ruby | Moderate to high |
| Strong pink | Pink sapphire | Lower than ruby |
| Too dark or light | Off-color ruby | Significantly lower |
Color quality depends on chromium content, low iron presence, and sometimes natural fluorescence—common in Burmese rubies.
2. Clarity and Inclusions
Unlike diamonds, rubies often contain inclusions. In fact, inclusions can help identify a ruby as natural. However, eye-clean rubies, especially over 1 carat, are rare and valuable.
Common ruby inclusions:
- Silk (rutile needles)
- Fingerprint inclusions
- Color zoning
Some rubies display asterism, forming star rubies, which are rare collector stones.
3. Size and Carat Weight
Rubies rarely form large, clean crystals. Stones above 2 carats with top-tier color and clarity are exceptionally rare. As size increases, so does rarity—exponentially.
| Size (Carat) | Relative Rarity |
|---|---|
| 0.5–1.0 ct | Rare |
| 1.0–2.0 ct | Very rare |
| 2.0+ ct | Museum-level rare |
4. Origin and Mining Conditions
Where a ruby is mined influences its rarity and quality.
| Origin | Characteristics | Rarity Level |
|---|---|---|
| Myanmar (Burma) | Fluorescence, rich red tone | Extremely rare |
| Mozambique | Larger sizes, slightly purplish hue | Rare |
| Madagascar | Light tones, good clarity | Moderate |
| Thailand | Darker stones, fewer gem-quality finds | Common |
Mines are depleting, which only increases the scarcity of the finest rubies on the market.
Ruby Rarity vs. Diamond Rarity: What’s the Real Difference?
Diamonds are considered precious, but that doesn’t mean they’re rare—at least not in the way many people think.
Rubies are among the rarest colored gemstones, especially when judged by gem-quality standards. When you compare a diamond and ruby side by side, the differences in formation, supply, and grading become very clear.
1. Geological Rarity: Rubies Win
- Rubies form under extremely specific conditions. They need just the right mix of heat, pressure, and chromium.
- The result? Small crystals with intense red color are very hard to find.
- Most quality rubies come from a few select locations like Myanmar and Mozambique.
- Diamonds, on the other hand, are found in large deposits across multiple continents and mined in massive volume.
2. Market Availability: Diamonds Are Abundant
- Colorless diamonds are mass-produced, sorted, and sold globally.
- The diamond trade is highly controlled to create an illusion of rarity.
- Colored diamonds (e.g., pink, blue) are rarer but still more available than top-grade rubies.
In contrast:
- Fine rubies with vivid color, minimal inclusions, and no heat treatment are even rarer than many fancy colored diamonds.
- Supply of natural, untreated rubies is extremely limited and shrinking.
| Gem Type | Market Supply | Gem-Quality Rarity |
|---|---|---|
| Colorless Diamonds | Very High | Moderate |
| Colored Diamonds | Low to Medium | Variable |
| Rubies | Very Low | Extremely High |
3. Grading Standards: Tougher on Rubies
- Diamond grading is standardized (4 Cs: color, clarity, cut, carat).
- Most diamonds in the market are lightly included or even flawless.
Ruby grading is much stricter because:
- Rubies rarely appear flawless—inclusions are common.
- Ruby clarity is judged differently—“eye-clean” is the standard, not “internally flawless.”
- Color grading focuses on hue, saturation, and tone, which are harder to standardize.
Result:
A ruby that meets strict grading standards is not just rare—it’s exceptional.
4. Treatment Prevalence: Another Key Difference
- Over 95% of rubies on the market are heat-treated to improve color and clarity.
- Only a tiny percentage of rubies remain untreated and natural.
- Most diamonds are not color-enhanced (though lab-created ones are on the rise).
This scarcity of untreated rubies keeps the price high and reinforces their reputation as a collector’s gemstone.
5. Investment Perspective
- Diamonds are not that rare, which limits their investment value over time.
- Ruby gemstones, especially large untreated ones, increase in value, as seen in auction results.
- The value of a ruby depends on color, clarity, size, origin, and whether it’s been treated.
Are Rubies a Good Investment Due to Their Rarity?
Yes—rubies are among the best long-term gemstone investments, especially when they meet strict gemological standards.
Traits of an Investment-Grade Ruby:
- Color: Vivid red to slightly purplish red
- Clarity: Eye-clean or close
- Treatment: None or minimal
- Origin: Preferably Burmese
- Carat: 1+ carat, with rising rarity at 3+
- Certification: GIA, AGL, SSEF, or equivalent
Tips:
- Only buy certified stones.
- Avoid synthetic or heavily treated rubies.
- Consider auction history for reference pricing.
- Long-term hold is key—these aren’t for flipping.
High-quality rubies often outperform diamonds in terms of value growth. They’re rarer, highly collectible, and difficult to replace on the open market.



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