Clarity Treatments

Inclusions are nature's fingerprints. Every diamond carries them — tiny crystals, feathers, clouds, and pinpoints formed during millions of years of growth deep in the earth's mantle. They are what make each stone unique. They are also what make many stones less valuable.

A dark inclusion visible to the naked eye can drop a diamond from SI1 to I1 — a jump that may reduce its market price by 30% or more. A surface-reaching fracture that catches light at certain angles can distract from the brilliance a well-cut stone should deliver.

Diamond clarity treatments address these problems directly. Rather than changing a diamond's colour, they target specific inclusions and fractures to make them less visible. The goal is practical: improve a diamond's apparent clarity so it looks cleaner to the eye, even if its clarity grade under GIA standards may not change.

Two methods dominate the field: laser drilling and fracture filling. They differ in almost every important way — permanence, GIA acceptance, durability, and the level of risk they present to the buyer.

How Do the Two Clarity Treatments Compare?

	Laser Drilling	Fracture Filling
What it does	Burns or dissolves dark inclusions through a microscopic channel	Fills surface-reaching fractures with glass-like material
Permanent?	Yes — the drill channel is a lasting feature	No — filler degrades with heat, chemicals, and cleaning
GIA grades it?	Yes — noted on the report and plotted on the clarity diagram	No — GIA returns the stone without a report
Visible at 10x?	Yes — thin, thread-like tunnel visible under magnification	Often — "flash effect" (orange/purple) under magnification
Durability risk	Low — safe for normal wear and most repairs	High — torch, ultrasonic, and steam cleaning all damage filler

Laser Drilling

A focused laser beam creates a microscopic tunnel — typically 0.05 mm or less in diameter — from the diamond's surface to a dark inclusion trapped inside. Once the channel is open, the inclusion can be vaporised by the laser itself or dissolved by introducing acid through the tunnel.

A more recent technique, internal laser drilling (the KM treatment), uses the laser to create an internal fracture that reaches the inclusion without leaving a visible surface hole. The resulting fracture resembles a natural feather, making it considerably harder to detect.

Laser drilling is permanent. GIA accepts laser-drilled diamonds for full grading, plots the drill channels on the clarity diagram, and notes the treatment on the report.

→ Full article: Laser Drilling

Fracture Filling

Fracture filling takes a different approach: rather than removing the inclusion, it hides the fracture. A glass-like substance with a refractive index close to diamond's is injected into surface-reaching cracks under vacuum conditions. The filler makes the fracture nearly invisible.

Pioneered by Zvi Yehuda in Ramat Gan, Israel during the 1980s, fracture filling can make a diamond appear one to two clarity grades better. But the filler is vulnerable to heat, chemicals, ultrasonic vibration, and steam cleaners.

The signature detection feature is the "flash effect" — when rotated under magnification, filled fractures produce bright flashes of orange and purple. GIA does not grade fracture-filled diamonds.

→ Full article: Fracture Filling

Disclosure: Non-Negotiable

Both the FTC and GIA require sellers to disclose any clarity treatment. This obligation is not optional, not situational, and not subject to the seller's judgment about materiality. If a diamond has been drilled or filled, the buyer must be told — before purchase, in writing.

Frequently Asked Questions

What is a clarity-enhanced diamond?

A clarity-enhanced diamond has undergone laser drilling, fracture filling, or both to reduce the visibility of inclusions or fractures. The term "clarity-enhanced" should always be accompanied by the specific treatment name.

Is a laser-drilled diamond a good value?

Laser-drilled diamonds offer a visually cleaner stone at 10–30% below untreated equivalents. The treatment is permanent, GIA-graded, and requires no special care. For budget-conscious buyers who prioritise visual appearance, they can represent genuine value.

Why won't GIA grade fracture-filled diamonds?

GIA requires that graded characteristics be durable. Fracture filling is impermanent — the filler can degrade with heat, cleaning, and time. A clarity grade that might change is inconsistent with GIA's standards.

Can a diamond be both laser-drilled and fracture-filled?

Yes. Some diamonds undergo laser drilling to access inclusions and fracture filling to hide the resulting channels or nearby fractures. Both treatments must be disclosed.

Laser Drilling — Full article on traditional and KM laser drilling methods
Fracture Filling — Full article on the filling process, detection, and care
Treated Diamond Care & Risks — Care protocols for each treatment type

Sources: GIA Diamond Treatments, GIA — Characteristics and Identification of Filled Diamonds, GIA Gems & Gemology Summer 2000 — New Lasering Technique