Q&A
Frequently Asked Questions
The questions buyers ask most about independent verification and diamond identity. Each group links to the full article.
Consumer ProtectionWhy a GIA-Certified Diamond Still Needs Independent Verification Before Trading in Vietnam
- Does a GIA report prove a diamond is genuine?
- A GIA report certifies the characteristics of the stone GIA examined when the report was issued. It does not automatically guarantee the diamond being traded today is that same stone, so a physical check is still needed before a high-value sale.
- Is the laser inscription on the girdle enough to verify a diamond?
- No. A girdle laser inscription is a useful identifier, but it can be applied to various diamond materials. A gemologist never relies on the inscription alone to establish a stone's identity.
- How do you tell a natural diamond from a lab-grown one?
- It requires dedicated CVD/HPHT detection equipment together with high-magnification microscopy and spectroscopic analysis. Matching weight, size, or cut is not enough to conclude.
- What does independent verification involve?
- Reading the GIA report, examining the stone with specialized instruments, matching the inclusion plot (the fingerprint), then issuing a confirmation and sealing the stone to preserve the link between the diamond and its paperwork.
- What is diamond identity verification?
- It is an independent step that confirms the diamond being examined is the one matching its GIA report, rather than grading quality again. It focuses on whether the stone has the correct identity.
- Why is the inclusion “fingerprint” more reliable than a laser inscription?
- Every natural diamond forms over billions of years, giving it a unique system of inclusions and internal features that cannot be copied. A laser inscription, by contrast, can be polished off, re-engraved, or faked.
- What equipment is needed to verify a diamond's identity?
- A professional laboratory combines several instruments: gemological and darkfield microscopes, fluorescence observation, CVD/HPHT detectors, spectrometers, and laser-inscription verification tools. No single instrument answers every question.
- What does Chain of Custody mean in diamond grading?
- It is the principle of sealing the stone immediately after verification to preserve identity continuity from the moment of grading to the transaction. Sealing does not certify quality; it prevents substitution after the stone has been checked.
- How is DIV different from a GIA report?
- A GIA report answers “what is this diamond's quality,” while DIV answers “is the stone in front of us the one that was certified.” DIV does not re-issue a quality report and does not replace a GIA report — the two services complement each other.
- Why does a diamond with an international certificate still need DIV?
- A certificate can be perfectly accurate, but if the stone has been substituted the paper is still genuine while the traded stone is no longer the certified one. The risk lies in the match between certificate and actual stone — exactly DIV's scope.
- What does the DIV process check?
- DIV reconciles geometry, carat weight and measurements, cut and girdle characteristics, the natural inclusion plot, optical and fluorescence behavior, and markers distinguishing natural from CVD/HPHT diamonds, then matches all of it against the certificate record.
- Does DIV rely only on the laser inscription?
- No. A laser inscription can be polished off, re-engraved, or faked, so it is only a supporting clue. DIV combines morphological, optical, and micro-structural evidence to reach a scientifically grounded conclusion.
Materials ScienceHardness Is Not Toughness — Harder Materials Are Often More Brittle
- Can a 10-Mohs diamond still be scratched or broken?
- Yes. The Mohs scale measures only scratch resistance, not impact resistance. A diamond is very hard to scratch, but it can still chip, crack, or break under a strong enough blow in the right direction.
- What is the difference between hardness and fracture toughness?
- Hardness (Mohs/Vickers) is resistance to scratching and deformation. Fracture toughness is resistance to crack propagation. Diamond has the highest hardness but a fracture toughness of only about 3–7 MPa·√m, far below many engineering metals.
- Why is a diamond's girdle the most chip-prone spot?
- The girdle is the stone's thinnest cross-section. Cut extremely thin, it becomes almost a weak point, where a single hard blow can produce a girdle chip. That is why laboratories always assess girdle thickness.
- Do small scratches reduce a diamond's brightness?
- Yes. Scratches, abrasion, nicks, or chips alter the path of light, so the stone leaks more light and loses reflection and dispersion — looking less bright and showing less fire, especially in high-cut-quality diamonds.
Economic PerspectiveThe Prestige of Diamond Jewelry
- Is diamond jewelry an investment vehicle?
- It should not be treated as one. Diamond jewelry is luxury consumption, bought first of all to be worn and to express status and personal value. The retail price includes cutting, shipping, insurance, marketing, retailer margin, and taxes — costs that largely vanish on resale.
- Why do diamonds usually resell below the purchase price?
- A second buyer will not pay the commercial costs baked into the retail price, and with jewelry they usually price only the diamond and the gold — paying almost nothing for design, craftsmanship, or brand. A stone bought for 300 million dong may correspond to only 180–220 million at international trading prices.
- When does a diamond count as a store of value or investment?
- Only in special cases: stones over 5 carats, D–F color, IF/VVS clarity, clear provenance, international certification, and very high cut quality — or natural fancy-color diamonds (pink, blue, red) with extremely limited supply. That is a highly professional market, not one for most buyers.
- Why are diamonds less liquid than gold bars?
- Gold bars can be sold at almost any shop, while every diamond is a one-of-a-kind asset — it must be checked for the right stone, the matching certificate, substitution, chips, and stated color and clarity. Transactions are therefore much slower, and identity verification (DIV) before trading becomes essential.
- How much value is lost when reselling diamond jewelry in international markets?
- In many developed countries, retail and buy-back are separate systems, so resale prices reflect current market value rather than the original retail price. In most cases a reseller can lose 50–70% of the purchase price; high-quality certified loose diamonds lose considerably less.
- Why do Vietnamese businesses offer diamond buy-back policies?
- Three main reasons: building customer trust (answering “what if I need to sell later?”), keeping customers long-term through successive trade-ups to larger stones, and recirculating inventory — bought-back stones can be resold after inspection, identity verification, and grading.
- Is an 8–10% buy-back deduction the market standard?
- No. It is a commercial incentive offered by certain businesses, conditional on the stone being in original condition, fully certified, and bought at that very system. Actual buy-back levels also depend on stone quality, supply and demand, brand, and each company's policy — not the diamond's intrinsic value.
- What is “Guaranteed Liquidity Value”?
- It is the part of a diamond's real-world value created by a business's trade-in policy and the ability to verify the stone's identity (DIV) — alongside the 4C standard. In Vietnam, a diamond's value lies in the whole ecosystem of services around it, not just the stone itself.