Introduction: A Secret Beneath the Surface
At first glance, Geuda sapphires look unremarkable — cloudy, whitish, and almost lifeless. But within these pale stones lies a secret waiting to be revealed through fire. Mostly found in Sri Lanka, Geuda sapphires are a gemmological paradox — undervalued in their raw form, yet capable of extraordinary transformation.
This blog explores the mysterious world of Geuda sapphires — what they are, how they’re treated, their place in the gem trade, and what makes them so important to sapphire lovers and traders around the world.
What Is a Geuda Sapphire?
Geuda (pronounced gay-oo-dah) refers to a variety of corundum (the mineral family that includes sapphires) that appears milky or translucent in its natural state. Geuda stones often show little to no visible colour before treatment, giving them a dull, “sleepy” look.
But don’t let that fool you. Geuda isn’t flawed — it’s unfinished. In the hands of a skilled gem burner, it can become a radiant blue sapphire, often indistinguishable (to the untrained eye) from its naturally vivid cousins.
Where Are Geuda Sapphires Found?
Sri Lanka — the legendary island of Ratna Dweepa, or ‘Gem Island’ — is the undisputed home of Geuda. Nearly 70–80% of the country’s rough sapphire output consists of this cloudy corundum. For decades, Geuda was discarded or sold as industrial-grade material — until someone realized it could be transformed.
In the late 20th century, Thai gem traders, working closely with Sri Lankan miners, pioneered heat treatment methods that turned Geuda into valuable blue sapphires.
The Alchemy of Heat Treatment
How It Works
Geuda stones typically contain rutile silk and other mineral inclusions that scatter light, giving them a hazy appearance. When heated to temperatures between 1500°C and 1800°C, these inclusions dissolve or re-align, allowing the sapphire’s true colour to shine through — often a deep, velvety blue.
Some stones also undergo low-oxygen heating, known as ‘blowpipe heating,’ to control how the colour emerges.
Before & After
| Stage | Appearance |
| Before Heating | Milky, dull, semi-transparent |
| After Heating | Transparent, saturated royal blue |
Is It Still Natural?
Yes — Geuda sapphires are natural sapphires. Heat treatment is an accepted, stable, and permanent enhancement — widely disclosed in the gem trade. However, unheated sapphires typically command higher prices due to their rarity and purity.
Gemological Identification
Even after heat treatment, a skilled gemologist can often identify a Geuda origin through:
– Raman or FTIR Spectroscopy
– Silk reformation patterns
– Fluorescence differences
– Internal zoning or ‘halo’ effects
Astrological Use of Geuda Sapphires
In Vedic astrology, blue sapphire (Neelam) is associated with Saturn (Shani) and is considered extremely powerful. However, many traditional astrologers recommend unheated or minimally treated stones for maximum astrological effect.
That said, a Geuda-origin heated sapphire is still a natural Neelam — and for many buyers, it’s a more accessible entry point into high-quality sapphire energies.
Should You Buy a Geuda-Origin Sapphire?
Yes, if:
– You want a natural sapphire at a lower price point
– You’re comfortable with disclosed heat treatment
– You want a richly coloured stone without paying premium unheated rates
But consider alternatives if:
– You need an unheated gem for astrological rituals
– You’re investing in long-term collector-grade pieces
Price vs. Value
| Type of Sapphire | Typical Price Range (per carat) |
| Geuda (Before Heating) | ₹500 – ₹2,000 |
| Geuda (After Heating) | ₹4,000 – ₹20,000+ |
| Unheated Blue Sapphire | ₹25,000 – ₹2,00,000+ |
At PreciousCarats.com
We honour the origin story of every gem — including Geuda sapphires. All our heat-treated stones are clearly disclosed and certified, so you know exactly what you’re buying. Whether you’re just beginning your sapphire journey or searching for an affordable, brilliant gem, a responsibly treated Geuda sapphire can be a beautiful choice.
FAQs
❓ Is Geuda the same as synthetic sapphire?
No. Geuda sapphires are natural stones — not lab-created.
❓ Does heat-treated Geuda fade over time?
No. The colour is stable and permanent under normal conditions.
❓ Can a Geuda stone be used for a Neelam remedy?
Yes — but always consult your astrologer. Some prefer unheated only.
Explore Our Curated Blue Sapphire Collection
💎 www.preciouscarats.com