Blue Sapphire vs Blue Topaz: Choosing the Right Blue Gemstone

Blue gemstones are among the most popular in fine jewelry, and two of the most commonly compared are blue sapphire and blue topaz. While both offer beautiful blue hues, they differ significantly in rarity, durability, price, and prestige. This guide helps you choose the right blue gemstone for your needs.

At a Glance

Property	Blue Sapphire	Blue Topaz
Hardness	9 (Mohs)	8 (Mohs)
Rarity	Rare	Common
Price/ct (fine)	$500-$5,000+	$5-$30
Color Range	Pale to vivid blue	Sky, Swiss, London blue
Durability	Excellent	Very Good
Best For	Engagement, heirloom	Fashion, everyday

Color Comparison

Blue Sapphire

Natural blue sapphires display a range from cornflower blue to deep royal blue, often with violet or green secondary tones. The most valued color is a vivid, medium-dark blue called "cornflower" or "Kashmir" blue. Sapphire color has depth and complexity that is difficult to replicate — the stone seems to glow from within. Kashmir, Burma, and Sri Lanka produce the finest blues.

Blue Topaz

Blue topaz comes in three recognized shades: Sky Blue (pale, icy), Swiss Blue (vivid, electric), and London Blue (deep, inky). Most blue topaz is colorless topaz that has been irradiated and heat-treated to produce these blues. The treatment is permanent and universally accepted. Swiss Blue is the most popular shade. See our topaz guide for more details.

Durability

Both are excellent for daily wear. Sapphire's 9 Mohs hardness makes it second only to diamond in scratch resistance — ideal for engagement rings. Topaz at 8 Mohs is also very scratch-resistant, though it has perfect cleavage in one direction, meaning it can split if struck sharply at the right angle. For rings worn daily, sapphire has a slight edge.

Price Difference

The price gap between sapphire and topaz is dramatic. A 1-carat fine blue sapphire may cost $1,000-$5,000 or more, while a 1-carat Swiss Blue topaz costs $10-$30. This means you can get a much larger topaz for the same investment, or invest in a high-quality sapphire for maximum long-term value. Lab-created sapphires offer a middle ground — same hardness and beauty at a fraction of natural sapphire prices.

Which Should You Choose?

Choose Blue Sapphire if:

• You want maximum durability for daily-wear rings
• Long-term value and prestige matter
• You prefer the complex, luminous color of natural sapphire
• You are purchasing an engagement or heirloom piece

Choose Blue Topaz if:

• investment is a primary consideration
• You want a large, impressive stone
• You prefer bright, vivid blue without violet tones
• The jewelry is for fashion or everyday accessories

Other Blue Gemstone Alternatives

If neither sapphire nor topaz is quite right, consider:

• Tanzanite: Violet-blue, rarer than sapphire but softer. Excellent for earrings and pendants. See our tanzanite guide.
• Aquamarine: Light blue with a serene, watery quality. Good durability and available in large sizes. See our aquamarine guide.

Browse our sapphire and blue topaz collections, and read our complete buying guide for more expert advice.