Reference
Industry Glossary
The working vocabulary of the diamond and jewelry trade — grading, certification, market metrics, and compliance terms, defined the way the industry actually uses them.
The 4Cs — Grading
- Carat
- The unit of diamond weight: 1 carat = 0.2 grams, divided into 100 points. Price per carat rises non-linearly at threshold weights (0.50, 1.00, 2.00 ct).
- Cut
- The grade of a diamond's proportions, symmetry, and polish — the only C determined by human craftsmanship. Cut drives brilliance more than any other factor.
- Clarity
- The absence of inclusions and blemishes, graded from Flawless (FL) to Included (I3). Most trade goods fall between VVS and SI.
- Color
- For white diamonds, the absence of color, graded D (colorless) to Z (light yellow/brown). Fancy colors are graded on a separate intensity scale.
- Fluorescence
- A diamond's glow under UV light, from None to Very Strong. Strong blue fluorescence typically discounts white goods, though it can improve the face-up appearance of lower colors.
Trade & Manufacturing
- Rough
- Uncut, unpolished diamonds as they come from the mine. Rough is sold through producer sights, auctions, and tenders before entering manufacturing.
- Polished
- A finished, faceted diamond ready for certification and sale. The rough-to-polished transformation typically loses 50–60% of the original weight.
- Melee
- Small polished diamonds, generally under 0.20 ct, sold in parcels by the carat and used as accent stones. Melee is the volume backbone of jewelry manufacturing.
- Sight / Sightholder
- De Beers' rough distribution system: authorized clients (sightholders) purchase pre-assembled boxes at scheduled sales events (sights) held roughly ten times a year.
- Tender
- A sealed-bid sale of rough or polished goods, used by producers and traders to achieve market-clearing prices on individual stones or parcels.
- Memo (Consignment)
- Goods released to a buyer for inspection or resale without transfer of ownership. The backbone of trust-based trading in bourses — and a key credit-risk exposure.
- Bourse
- A diamond exchange — a membership-based trading floor with binding arbitration. The World Federation of Diamond Bourses (WFDB) links 27 exchanges including Ramat Gan, Antwerp, Mumbai, and New York.
Certification & Provenance
- GIA
- The Gemological Institute of America — the reference standard for diamond grading. A GIA report is the de-facto pricing baseline for polished goods above ~0.30 ct.
- Certificate (Cert)
- A laboratory grading report documenting a stone's 4Cs and measurements. 'Cert goods' trade at transparent list-based discounts; 'no-cert' goods rely on trader judgment.
- Inscription
- A microscopic laser marking on a diamond's girdle, usually the certificate number, enabling identification and matching stone to report.
- Lab-Grown Diamond (LGD)
- A diamond produced by HPHT or CVD processes — chemically identical to natural but priced on a separate, steadily declining curve. Disclosure is mandatory in every major market.
- Kimberley Process (KPCS)
- The intergovernmental certification scheme (2003) that regulates rough diamond trade to prevent conflict diamonds. Every cross-border rough shipment requires a KP certificate.
- Provenance / Traceability
- Documented origin of a diamond from mine to market. Once a marketing feature, now a regulatory requirement under G7 import rules for Russian-origin goods.
Market & Pricing
- Rapaport Price List (the List)
- The weekly benchmark price grid for polished diamonds by shape, size, color, and clarity. Trades are quoted as discounts (or premiums) to the List.
- RAPI
- The Rapaport Diamond Index — tracks average asking prices of certified polished diamonds, the trade's shorthand for polished market direction.
- Rough Index (Zimnisky)
- The Zimnisky Global Rough Diamond Price Index — a weighted composite tracking rough prices across producer sales and tenders.
- Discount / Below Rap
- The percentage below the Rapaport List at which a stone actually trades — the real price signal. A 'tightening discount' means strengthening demand.
- Price per Carat (PPC)
- Total price divided by carat weight — the standard unit of comparison across stones and parcels, especially in rough and melee.
Compliance & Regulation
- G7 Import Restrictions
- The 2024+ framework banning Russian-origin diamonds from G7 markets, phasing in traceability-based verification for imports above threshold sizes.
- OFAC
- The US Treasury's Office of Foreign Assets Control — administers sanctions lists (SDN) that diamond firms must screen counterparties against.
- AML / KYC
- Anti-Money-Laundering rules and Know-Your-Customer procedures. Dealers in precious stones are 'covered businesses' under the US Bank Secrecy Act and equivalent EU rules.
- Due Diligence (OECD)
- The OECD five-step framework for responsible mineral supply chains — the basis for industry schemes like the WDC System of Warranties and RJC certification.
- RJC
- The Responsible Jewellery Council — the industry's certification body for responsible business practices across the jewelry supply chain, from mine to retail.