What is H-FH? Decoding "Heat with Fissure Healing"

H-FH (Heat with Fissure Healing), colloquially called "heat with flux" or "borax healing," is an advanced treatment primarily applied to rubies, sapphires, and other corundum gemstones. This process targets microscopic fissures natural fractures formed during a gem’s geological creation.

By heating stones to 1,300–1,800°C while applying a flux agent (typically borax, lead glass, or other compounds), the melted flux flows into fractures, optically "healing" them. Dramatically improved clarity and marketability.

The Science Behind H-FH: Step by Step

Pre-Treatment Selection: Low-clarity stones with surface-reaching fissures are chosen.

High-Tea Heat Exposure: Gems are heated in kilns beyond 1,300°C.

Flux Introduction: Borax or similar flux melts into liquid, capillary action pulls it into cracks.

Cooling & Solidification: As temperatures drop, flux hardens, creating glass-filled veins.

Polishing: Final buffing removes surface residue, revealing enhanced transparency.

The Gemological Institute of America (GIA) explains how flux healing alters light behavior in gems, while MIT’s Earth Sciences Department notes that such treatments mimic natural "healing" events under extreme crustal conditions.

Why Treat Gems, The Industry’s Open Secret

Clarity Overhaul: Removes distracting inclusions, boosting light performance.

Value Resurrection: Upcycles low-grade stones (e.g., milky rubies) into viable jewelry candidates.

Market Demand: 95% of commercial rubies are heat-treated (per GIA reports).

Crucially, H-FH is permanent – unless re-exposed to extreme heat (e.g., jeweler’s torch).

H-FH vs. Natural:

Factor H-FH Treated Untreated

Clarity Artificially enhanced Naturally occurring

Rarity Common Exceptionally rare

Price 30-70% lower Premium (up to 300%+)

Disclosure Requirement Mandatory by FTC rules N/A

H-FH gems are not "fake" they’re natural stones with human-assisted improvements. But undisclosed treatments constitute fraud.

Buyer’s Defense Kit: 5 Must-Ask Questions

"Is this gemstone treated? Specifically, has it undergone H-FH or flux healing?"

"Can I see a lab report from GIA, AGL, or Gübelin?"

"What’s the exact nature of filler material used?" (Borax? Glass? Lead?)

"Does treatment impact durability for my setting type (e.g., rings vs. pendants)?"

"Is pricing adjusted for treatment versus untreated equivalents?"

Use a 10x loupe to inspect for "flash effects" ,trapped gas bubbles or flow patterns in healed fissures.

Why CaratX Guarantees Transparent H-FH Sourcing

At CaratX, every H-FH treated gemstone is:

Certified: Treatment history logged immutably.

Pre-Shipment Verified: Third-party lab validation included.

Priced Honestly: Compare untreated vs. treated rubies or sapphires with real-time market data.

For Sellers: Leverage our global marketplace to ethically sell treated/untreated gems:

Zero listing fees + 1-week shipping via Seller Program

Access 18+ countries – Launch products seamlessly

For Buyers:

Shop investment-grade untreated diamonds

H-FH democratizes beauty transforming flawed stones into wearable art. But its value hinges on transparency. Insist on disclosure, demand certifications, and partner with platforms like CaratX that engineer trust into every transaction.

Ready to buy or sell with radical honesty? Register as a CaratX Seller

Explore Untreated Diamonds

Knowledge is your loupe. Shine it on every purchase

Conclusion -

H-FH is one of the jewelry industry’s most transformative treatments turning flawed gems into brilliant, wearable art. By filling fissures with flux under high heat, this process revives clarity, enhances light performance, and makes beautiful stones accessible at lower prices.

CaratX champions radical transparency by providing certified treatment histories, verified pricing, and global selling opportunities. Whether buying or selling, knowledge and honesty are the true measures of value in the gemstone world.

Image Credit - The Jewelers Network