Sapphire, Emerald, Ruby: A Complete Guide to Precious Gemstones
Diamonds aren't the only precious gemstones worth owning. In fact, sapphires, emeralds, and rubies command higher prices per carat than diamonds and carry cultural significance that spans centuries.
Yet most buyers bypass colored gemstones entirely, intimidated by conflicting quality standards, unclear sourcing, and confusion about value. This guide demystifies the big three gemstones and explains what actually determines their worth—and beauty.
The Big Three: Ruby, Sapphire, and Emerald
These three are classified as "precious gemstones" (distinct from "semi-precious" alternatives). Their rarity, durability, and beauty position them as top-tier investments.
Ruby: The Rarest and Most Valuable
What it is: Red corundum. The chromium in the crystal structure creates the red hue.
Rarity: Rubies are rarer than diamonds. Fine-quality rubies command prices 10–100x higher per carat than diamonds.
Hardness: 9 on Mohs scale (only diamonds at 10 are harder). Exceptionally durable for daily wear.
Color variations:
- Pigeon's blood red: The most prized color—vivid, pure red with slight blue undertone. Originally from Burma (Myanmar). Extremely expensive.
- Deep red: Rich, dark red with strong saturation. Slightly less valuable than pigeon's blood.
- Pinkish red: More affordable, still beautiful, suitable for everyday wear.
Quality indicators:
- Color saturation: More vivid = more valuable
- Transparency: Clarity matters (fewer inclusions = higher value)
- Origin: Burmese rubies command 10–20% premiums over Thai or African rubies
- Treatment: Natural, unheated rubies are rarest; heat treatment is common and acceptable
Price range: R5,000–R100,000+ per carat for fine quality. Budget rubies R1,000–R3,000 per carat.
Investment potential: High. Fine rubies appreciate annually and hold value exceptionally well.
Best for: Collectors, those wanting a statement piece, investment-minded buyers.
Sapphire: The Versatile Gemstone
What it is: Blue corundum (same mineral family as ruby, different chromium concentrations create the blue).
Rarity: Less rare than ruby, more rare than emerald. Blue sapphires are readily available; colored sapphires are rarer.
Hardness: 9 on Mohs scale, same as ruby. Extremely durable.
Color variations:
- Cornflower blue: The classic, most prized sapphire color. Bright, saturated blue.
- Royal blue: Deeper, more sophisticated blue. Equally valuable.
- Midnight blue: Very dark, almost navy. Less valuable (too dark to sparkle well).
- Fancy sapphires: Pink, yellow, orange, green, white (colorless). Increasingly popular; some command high prices.
Quality indicators:
- Color saturation: Vivid colors are rarest
- Transparency: Few inclusions desired
- Origin: Kashmir and Burmese sapphires premium 15–30%; Sri Lankan and Australian sapphires more affordable
- Treatment: Heat treatment is standard and accepted; accepted treatments don't affect value significantly
Price range: R3,000–R50,000 per carat for fine blue sapphires. Fancy sapphires R2,000–R20,000 per carat.
Investment potential: Moderate to high, depending on origin and color.
Best for: Engagement rings (durable + beautiful), collectors, those wanting color without break-the-bank pricing.
Emerald: The Temperamental Treasure
What it is: Green beryl. Chromium and vanadium create the green color.
Rarity: Relatively available compared to ruby and sapphire, but fine-quality emeralds are rare.
Hardness: 7.5–8 on Mohs scale (softer than ruby and sapphire). Requires more careful handling.
Color variations:
- Vivid green: The most prized. Deep, rich green without being muddy.
- Grass green: Medium-toned, lighter green. Less valuable.
- Yellow-green: Affordable but less desirable.
Clarity challenges: Emeralds are inherently included. Most emeralds have "gardens" of inclusions. Perfectly clear emeralds are extraordinarily rare and expensive.
Quality indicators:
- Color saturation: More vivid = more valuable
- Origin: Colombian emeralds command premiums (25–40% higher). Zambian and Brazilian emeralds more affordable.
- Treatments: Oil treatment is standard and expected (fills surface fractures, improves appearance). Doesn't diminish value if done properly.
Price range: R2,000–R80,000+ per carat for fine quality. Budget emeralds R500–R2,000 per carat.
Investment potential: Moderate. Emeralds hold value but don't appreciate as strongly as rubies.
Best for: Statement pieces, collectors, those drawn to green, engagement rings (with careful handling).
Gemstone Quality: How to Evaluate Beyond the Label
Unlike diamonds, which have the standardized 4Cs, gemstones are evaluated more subjectively. Here's what actually matters:
1. Color (The Most Important Factor)
For colored gemstones, color is paramount. This is where certified gemstones have real value—the certification confirms the color authenticity.
Ask yourself:
- Is the color vivid, or washed out?
- Is it pure (no secondary tones), or does it lean toward another color?
- Is it deep enough, or is it pale?
The most valuable gemstones have saturated, pure color—not too light, not too dark.
2. Clarity (Less Important Than for Diamonds)
Colored gemstones are inherently included. Perfect clarity is rarer—and sometimes impossibly expensive for little visual gain.
The clarity hierarchy:
- Eye-clean: No visible inclusions to the naked eye. Standard for fine gemstones.
- Loupe-clean: Inclusions visible only under 10x magnification. Acceptable quality.
- Slightly included: Small inclusions visible to the naked eye. Budget-friendly; still beautiful.
- Heavily included: Obvious inclusions that affect transparency. Avoid unless you love the look.
Practical advice: Buy "eye-clean" gemstones. Don't pay premiums for loupe-clean unless the color is exceptional.
3. Carat Weight
Larger gemstones are rarer and command exponential price increases. A 3-carat sapphire costs far more than 3x the price of a 1-carat sapphire.
The gem geometry: A 2-carat gemstone may look only 1.3x larger than a 1-carat gemstone (because volume increases cubically with weight, but visible size increases linearly with diameter).
This means you can often get away with slightly smaller gemstones visually while saving significantly on cost.
4. Origin (Critical for Investment)
Ruby and sapphire values fluctuate dramatically based on origin.
Premium origins:
- Ruby: Burma (Myanmar) > Thai > African
- Sapphire: Kashmir > Burma > Sri Lanka > Australian
- Emerald: Colombian > Zambian > Brazilian
An "origin certificate" from GRS (Gemresearch Swisslab) or Gubelin is worth the R1,000–R2,000 investment for gemstones over R30,000. It confirms origin and increases resale value.
5. Treatment Acceptance
Most colored gemstones are treated. The key is understanding what treatment was done and whether it's stable.
Accepted treatments:
- Heat treatment (ruby, sapphire, emerald): Standard, expected, stable.
- Oil filling (emerald): Standard, expected, requires re-oiling periodically (R200–R500 per treatment).
Avoided treatments:
- Glass filling: Unstable, not accepted in investment circles.
- Irradiation: Creates color artificially; fades over time.
Always verify treatment disclosure. A gemstone without treatment costs significantly more but holds value better.
Gemstone vs. Diamond: Investment Comparison
Why choose gemstones over diamonds?
- Uniqueness: Colored gemstones are more distinctive. Your sapphire engagement ring won't look like everyone else's.
- Value per carat: A fine ruby is rarer and more valuable than an equivalent carat diamond.
- Symbolism: Rubies, sapphires, and emeralds carry cultural significance. They're not just commodities.
- Aesthetics: Color is inherently more interesting than colorless. Many find colored stones more visually striking.
Why diamonds might be better:
- Standardized grading: The 4Cs make diamond buying more straightforward.
- Larger market: Diamonds have more secondary market liquidity (easier to resell).
- Durability: Diamonds are slightly harder (10 vs. 9), making them more scratch-resistant.
- Tradition: Engagement diamonds are culturally entrenched.
The practical truth: Colored gemstones are superior investments for serious collectors. But diamonds offer more accessibility and standardization for average buyers.
Gemstone Jewelry Care and Maintenance
Colored gemstones require different care than diamonds.
Ruby and Sapphire Care
- Cleaning: Safe with warm water, mild soap, soft brush. Can handle most household cleaning products.
- Durability: Suitable for daily wear (engagement rings, everyday jewelry).
- Heat resistance: Stable under normal conditions; avoid extreme temperature changes.
- Frequency of professional service: Annual inspection for setting security.
Emerald Care (Special Considerations)
- Avoid water exposure: Oil treatment can wash away with repeated water exposure.
- Avoid chemicals: Harsh cleaners can damage the oil treatment.
- Cleaning method: Use only lukewarm water and mild soap. Pat dry immediately.
- Re-oiling: Professional re-oiling every 2–3 years (R200–R500).
- Storage: Store separately from other jewelry to prevent scratching.
- Daily wear: Emeralds are softer than rubies/sapphires. Better for rings you remove occasionally than daily engagement rings.
Gemstone Investment Strategy
If you're buying colored gemstones as an investment (not just for aesthetics):
Tier 1: Fine Investment Gemstones
- Premium origin (Burmese ruby, Kashmir sapphire, Colombian emerald)
- Vivid, saturated color
- Eye-clean to loupe-clean clarity
- Natural, no treatment (or only accepted heat treatment)
- Certified by GRS or Gubelin
- 2+ carats (larger stones appreciate more)
Price range: R50,000–R500,000+ Annual appreciation: 5–10% historically Liquidity: Slower to sell, but strong collector demand
Tier 2: Semi-Investment Gemstones
- Secondary origin (Thai ruby, Sri Lankan sapphire, Zambian emerald)
- Good color saturation
- Eye-clean clarity
- Standard treatments accepted
- Certified by reputable lab
- 1–2 carats
Price range: R15,000–R50,000 Annual appreciation: 2–5% historically Liquidity: Easier to sell locally; broader market
Tier 3: Lifestyle Gemstones
- Any origin
- Beautiful color (not necessarily museum-quality)
- Slightly included acceptable
- No certification required
- Under 1 carat or any size
Price range: R2,000–R15,000 Purpose: Personal enjoyment, not investment Liquidity: Harder to resell; focus on enjoyment, not appreciation
FAQ: Precious Gemstones
Q: Is a treated gemstone worth less than an untreated one? A: Heat treatment is standard and expected. It doesn't reduce value if disclosed. Glass-filling or irradiation significantly reduces value. Always verify treatment.
Q: Can I wear a sapphire engagement ring daily? A: Yes. Sapphires are 9 on Mohs hardness (only slightly softer than diamonds). They're excellent for daily-wear engagement rings.
Q: Can I wear an emerald engagement ring daily? A: Less ideal. Emeralds are 7.5–8 hardness and inherently fragile. If you want an emerald, choose an engagement ring you remove for activities (sports, dishwashing, gardening). Wear it when dressing up or working in a safe environment.
Q: What's the difference between a ruby and a red diamond? A: A ruby is corundum; a red diamond is diamond. Red diamonds are extraordinarily rare and expensive (R100,000+ per carat). Rubies offer better value.
Q: Should I buy a gemstone online or in person? A: In person, if possible. Gemstone color is difficult to judge online; lighting and screen color distortion affect perception. If buying online, request certification and return policy.
Q: How can I verify a gemstone's authenticity? A: Get a lab certification from GRS, Gubelin, or similar. The certification tests hardness, density, refractive index, and confirms whether the gemstone is natural or synthetic.
Q: Will my gemstone depreciate if I resell it? A: Probably, but less than you'd expect. Jewelry retail markups are 40–60%, so resale is always discounted. Fine gemstones (especially rubies) hold value better than diamonds proportionally.
Q: Is a synthetic ruby worse than a natural ruby? A: Different, not worse. Lab-created rubies are chemically identical to natural rubies. They cost 80–90% less. If you want a large, beautiful ruby and don't care about origin story, lab-created is excellent value. If you want investment-grade, natural is essential.
Q: Can I insure a colored gemstone? A: Yes. Get the gemstone appraised and insured with a jewelry-specific policy. Coverage includes loss, theft, and damage.
The Bottom Line: Why Choose Colored Gemstones
Colored gemstones offer what diamonds don't: rarity, color, cultural significance, and investment potential. A fine ruby will outappreciate most diamonds over time. An emerald will mark you as someone with discerning taste.
Buying a colored gemstone is buying a piece of Earth's rarest beauty. It's an investment and a statement in one.
Ready to explore sapphires, emeralds, or rubies? Browse Pura's gemstone collection or schedule a consultation with our team. We can help you understand which gemstone aligns with your values and budget—and how to authenticate your purchase.