Last Updated: April 2026
TL;DR:
- Yes, diamonds with visible black spots are cheaper — the discount typically runs 10-30% depending on how visible the carbon inclusion is to the naked eye.
- Black spots are uncrystallized carbon trapped inside the diamond during formation, and they’re one of the most common inclusions the GIA grades on the clarity scale.
- Laser drilling can shrink or dissolve a black spot, but GIA-graded, laser-drilled stones typically sell for 30-60% less than untreated diamonds of comparable clarity.
Diamonds form 150-200 km below the earth’s surface under roughly 1,000°C of heat and 825,000 psi of pressure — conditions violent enough that not every carbon atom crystallizes cleanly. What’s left behind are black spots: pockets of carbon with a different molecular structure that blocks light instead of refracting it. Here’s exactly how much they cost you, and what your options are. For a broader look at what these actually are, see our companion piece on whether all diamonds have black spots.
What Are Black Spots in a Diamond?
Black spots are dots of carbon that never fully crystallized into diamond during formation. They’re a natural inclusion, not a defect caused by mishandling, and they appear black because their crystal structure blocks light rather than letting it pass through like the surrounding diamond.
These spots are chemically still carbon — the same element as the diamond around them — but their internal matrix is different enough that light can’t travel through cleanly. That’s why they read as opaque black dots rather than clear or colored inclusions like feathers or pinpoints.
Why Do Carbon Spots Form in Diamonds?
The exact cause isn’t fully settled, but a few explanations are widely accepted: the spot may mark the original crystal nucleus that failed to fully convert, uneven heat or pressure distribution during formation, trace mineral contamination, or exposure to high concentrations of nitrogen or boron deep underground. Since every rough diamond forms under similar extreme conditions, why some come out crystal clear and others carry visible carbon remains part science, part mystery.
Are Black Spots in Diamonds Bad?
Black spots aren’t structurally dangerous by themselves, but larger ones can indicate a weak point in the stone that’s more prone to cracking or cleaving under a sharp impact or rapid temperature change. Small spots invisible to the naked eye have essentially no practical downside.
The real issue is almost always cosmetic rather than structural — a visible black spot in the center of a white diamond disrupts the sparkle you’re paying for, which is why clarity grading exists in the first place.
How Do Black Spots Affect a Diamond’s Clarity Grade?
Diamonds with black spots visible to the naked eye are typically graded I1 clarity or lower on the GIA scale, while spots only visible under 10x magnification keep a diamond in the SI (Slightly Included) range or better. The more visible the spot, the lower the grade and the lower the price.
According to GIA, clarity is graded on a scale from Flawless down through Included, and carbon inclusions are one of the most common reasons a stone lands in the lower half of that scale.
Are Diamonds with Black Spots Cheaper?
Yes. Black spots lower a diamond’s clarity grade, which directly reduces price under the GIA’s 4Cs system (color, clarity, cut, carat). A visible black spot can also force a cutter to sacrifice carat weight or an ideal cut shape just to minimize the inclusion, compounding the discount.
If a black spot is visible without magnification, the stone generally can’t command a premium price no matter how good its color or cut grade is. Buyers can use this to their advantage — a diamond with a black spot hidden near the girdle or under a prong can offer significant savings with almost no visible tradeoff.
How Do You Make a Diamond’s Black Spot Less Visible?
Regular professional cleaning removes surface dust and grime that makes black spots and dullness more noticeable, and a bezel or prong setting can physically hide a black spot located near the diamond’s edge. Laser drilling is the most aggressive option but comes with real tradeoffs.
Laser drilling burns a microscopic channel — roughly 0.2 to 0.5mm wide — down to the black spot, then dissolves it with acid or heat and fills the resulting cavity with a glass-like filler. The treatment is permanent, must be disclosed by law under FTC rules, and GIA reports note every drill hole. The tradeoff: laser-drilled diamonds typically sell for 30-60% less than an untreated stone of similar visible clarity, and the filler material can shift slightly in color over time. A bezel setting is the safer, reversible option if the spot sits near the stone’s edge — it simply won’t help if the spot is dead center.
Should You Buy a Diamond with a Visible Black Spot?
If the spot is genuinely invisible to the naked eye and only shows under a jeweler’s loupe, buying that stone is a smart way to get more diamond for less money. If the spot is visible at arm’s length in normal lighting, it’s worth weighing the discount against how much the flaw will bother you daily — since resale value will reflect that same visible flaw down the line.
The Bottom Line
Black spots are a normal, natural part of how diamonds form, not a manufacturing flaw — but they do lower clarity grade and price in direct proportion to how visible they are. A small, well-hidden black spot can be a genuine bargain; a large, centered one is worth negotiating hard on or setting in a design that masks it. For more on how flaws affect long-term value, see our guide on why diamond resale value is so low.
Frequently Asked Questions
Do all diamonds have black spots?
No — many diamonds have no visible carbon inclusions at all, especially higher clarity grades like VVS or Flawless. Black spots are common but far from universal, and their presence is exactly what clarity grading is designed to measure.
How much cheaper is a diamond with a black spot?
It depends on visibility and size, but a stone with a naked-eye-visible black spot typically sells for 10-30% less than a comparable stone without one. Laser-drilled diamonds treated to remove a spot can sell for 30-60% less than an untreated stone.
Can a jeweler remove a black spot from a diamond?
Yes, via laser drilling, though the process is permanent, must be disclosed, and slightly weakens the stone’s structural integrity. It’s usually only worth it for diamonds with an otherwise strong clarity grade held back by one prominent spot.
Are black spots the same as diamond flaws?
Black spots are one specific type of inclusion, alongside others like feathers, pinpoints, and clouds. All of these fall under the umbrella of clarity characteristics that the GIA grades, but black carbon spots tend to be the most visually noticeable.
Is it bad to buy a diamond with an SI clarity grade?
Not necessarily — SI (Slightly Included) diamonds often look flawless to the naked eye and offer meaningful savings over VS or VVS grades. It’s one of the best value zones in the clarity scale for buyers who don’t need microscope-level perfection.
Tiger is a fashion&jewelry lover. He is also a fashion jewelry manufacturer that help thousands of small business to grow and also do business with some big fashion jewelry brands. He is a truly metal expert and he will share some information you are looking for.