How to use this glossary
This glossary defines the 60+ terms a South African diamond buyer needs to understand before any serious purchase. Definitions reflect the editorial team’s research as of the publication date. For full category guides see the links at the end of each definition. Terms are grouped by theme.
The 4Cs
The 4Cs at a glance
Carat. The unit of weight for a diamond, equal to 0.2 grams (200 milligrams). Carat is the most important variable for visible size and the most influential single factor in the per-stone price. A 1.00 carat diamond is roughly 6.5 mm in diameter for a round brilliant cut.
Cut. The proportions, polish, and symmetry of a finished diamond. GIA grades cut on a 5-grade scale: Excellent, Very Good, Good, Fair, Poor. Cut is the most important variable for visual sparkle and (in our editorial view) the most under-appreciated of the 4Cs by SA buyers.
Colour. The body colour of the diamond, graded D (best, colourless) to Z (lowest, lightly tinted). For engagement rings, G colour is the sweet spot for visually-colourless value in white-metal settings; J or K is acceptable in yellow-gold settings (the warm metal masks tinted body colour).
Clarity. The quantity, size, and visibility of inclusions and blemishes in the stone. Graded Internally Flawless (IF, best), VVS1, VVS2, VS1, VS2, SI1, SI2, SI3, I1, I2, I3 (lowest). For engagement rings, VS1 to eye-clean SI1 is the recommended range.
GIA grading and certification
GIA. The Gemological Institute of America, the global gold standard for diamond grading. Founded 1931. GIA grades every stone using the 4Cs and issues a numbered Diamond Grading Report verifiable at gia.edu/report-check.
GIA Report. The numbered grading certificate issued by GIA, with the report number laser-inscribed on the stone’s girdle. SA buyers above R30,000 should insist on GIA reports for every stone.
GIA Diamond Origin Service. GIA’s optional provenance-traceability programme that records the country of mining origin alongside the stone’s 4Cs grades. Available for participating cutting houses (Millennium Diamonds in SA participates).
AGS Ideal. The highest cut grade from the American Gem Society Laboratories. Tighter precision than GIA Excellent. AGS Ideal stones command 15 to 25 percent premium over GIA Excellent.
EGL. European Gemological Laboratories, an alternative grading body. EGL grading is roughly 10 to 15 percent cheaper than GIA but runs looser, especially on colour. Increasingly distrusted by US and UK buyers. SA buyers above R30,000 should prefer GIA over EGL.
IGI. International Gemological Institute, commonly used for lab-grown diamond grading and Indian-trade certification. I do not rely on it for serious natural-diamond buying in South Africa; I prefer GIA for natural stones.
Excellent cut. The highest GIA cut grade. Indicates excellent proportions, polish, and symmetry. The recommended cut grade for engagement rings at 1 carat and above.
South African supply-chain tiers
De Beers Sightholder. One of approximately 85 globally-approved companies with multi-year direct rough supply contracts from De Beers Global Sightholder Sales. SA Sightholders include Diacore and Diamcad. Sightholder-cut polished commands roughly 3 to 5 percent premium over comparable OTC stones.
De Beers DBCM Emerging Beneficiation Customer. A South Africa-only De Beers programme operating under the SA Diamond Beneficiation Act 2007. Allocates rough diamonds from De Beers’ SA mines (Venetia, Voorspoed, Cullinan) to approved SA cutting houses. The 2019 cohort includes Prodiam Trading. Different from Sightholder; one tier below.
OTC trade (Open-market trade). Cutting houses and dealers that source rough on the secondary market without direct miner contracts. Most working SA cutters operate at this tier. Natural-diamond examples I still use for comparison include Nungu, Eriksons, Millennium, Daneel, CaratCo, and The Diamond Works.
Beneficiation Act 2007. South African Diamond Beneficiation Act, the legislative framework requiring a percentage of De Beers’ SA-mined rough to be cut and polished within South Africa. Supports SA cutting-industry sustainability and black economic empowerment.
SADPMR. South African Diamonds and Precious Metals Regulator. The statutory body that licenses every SA business handling diamonds, gold, or precious metals. Mandatory registration for any SA diamond supplier. Verify at sadpmr.co.za.
SADDC. South African Diamond Dealers Club. The SA trade body for diamond dealers and wholesalers. Member directory at diamonds.org.za.
Jewellery Council of South Africa. The SA trade body for retail jewellers and manufacturing jewellers. Member directory at jewellery.org.za.
Trade pricing terms
Rapaport price list. The diamond industry’s reference benchmark for wholesale pricing of GIA-graded polished diamonds. Published weekly via store.rapaport.com. Subscription $250 to $350 per year.
RAP minus. Trade convention for quoting wholesale prices as a discount off the Rapaport list. “RAP minus 30 percent” means a 30 percent discount off the current Rapaport list price for that exact spec.
RAP list. Same as Rapaport price list. Industry shorthand.
Wholesale. The trade-tier transaction between cutting houses or distributors and the retail jeweller. Wholesale pricing is typically 30 to 50 percent below retail at the same GIA spec.
Manufacturer-direct. Buying directly from the diamond cutting house (rather than through a distributor or retail jeweller). The lowest layer of the 5-layer pricing stack accessible to small-and-mid retail buyers. SA examples I compare on this natural-only site: Prodiam, Nungu, Eriksons, Millennium, and The Diamond Works.
Trade pricing. Pricing offered to credentialed jewellers and dealers, typically 30 to 40 percent below US retail and 25 to 35 percent below SA boutique retail for the same spec.
Parcel pricing. Pricing for a batch (parcel) of stones bought together rather than per-stone. Parcel-tier purchases (typically 15 to 25+ stones) unlock 2 to 4 percent additional discount versus single-stone pricing.
Stone characteristics
Round brilliant. The most popular diamond cut, accounting for roughly 75 percent of all engagement-ring purchases worldwide. 57 to 58 facets (depending on culet) maximise light return for sparkle.
Fancy shape. Any non-round diamond cut. Includes oval, marquise, pear, emerald, asscher, cushion, princess, radiant, heart. Fancy shapes typically price 10 to 30 percent below round brilliants of the same colour and clarity.
Brilliant cut. Any cut with triangular and kite-shaped facets that maximize light return. Round brilliant, oval, marquise, pear, and heart are all brilliant cuts.
Step cut. Cuts with rectangular facets in steps. Emerald cut, asscher, and baguette are step cuts. Step cuts produce a hall-of-mirrors visual rather than sparkle. Inclusions show more in step cuts; insist on VS1-VS2 clarity.
Melee. Small diamonds, typically 0.05 to 0.20 carat each, used in tennis bracelets, halo settings, eternity bands, and pavé designs. Sold as parcels rather than individually certified.
Calibrated melee. Melee that has been sized and cut to consistent tight-tolerance specifications, used for matched parcels in jewellery. Calibrated melee from in-house cutters (like Prodiam) tends to be more uniform than distributor-sourced melee.
Pavé. A setting style where small diamonds (melee) are set close together in metal so the surface appears paved with diamonds. Common in halo settings and eternity bands.
Solitaire. A single-stone setting. The most common engagement-ring style. Maximises focus on the centre stone.
Halo. A setting style with a centre stone surrounded by a ring of small diamonds (melee). Visually amplifies the centre stone (a 1.00 ct centre with halo reads like 1.30 to 1.50 ct).
Three-stone. A setting with three diamonds, traditionally representing past, present, and future. Centre stone larger; side stones typically half the centre’s carat weight.
Eternity band. A band with diamonds set continuously around the entire ring (full eternity) or partially (half eternity). Cannot be resized because the stones run continuously. Most-bought for wedding bands and milestone anniversaries.
Tennis bracelet. A flexible bracelet of identical or graduated diamonds set in a continuous line. Named after a 1987 US Open incident. SA tennis bracelets typically use 50 stones at 0.05 to 0.20 carat each.
Tennis necklace. A continuous line of diamonds around the neckline, typically 16 to 22 inches. Standard 16-inch uses 80 to 150 stones. The highest-AOV SA category after large solitaire engagement rings.
Setting and metal terms
18ct white gold. Gold alloy at 75 percent gold purity (75/100 = 18/24 carat) with the remaining 25 percent silver, palladium, or other white-metal alloys. The SA default for engagement rings, wedding bands, and most jewellery.
Platinum. A naturally white precious metal. Roughly 60 percent more expensive than 18ct white gold at the same width. Heavier on the finger, holds prongs tighter, resists wear better.
9ct white gold. Gold alloy at 37.5 percent gold purity (9/24 = 37.5%). Cheaper than 18ct but discolours faster around prongs. Acceptable for non-stone-setting daily-wear jewellery; not recommended for engagement rings.
Setting. The metalwork that holds the diamond in the ring or other piece. Common types: prong, bezel, channel, pavé, tension.
Prong setting. Diamond held in place by 4 or 6 metal claws (prongs). Most common engagement-ring setting. Prongs need re-tipping every 5 to 10 years.
Bezel setting. Diamond fully surrounded by a metal rim. Most secure setting for daily wear. No prongs to re-tip.
Channel setting. Diamonds set in a continuous channel between two metal walls. Common for wedding bands and eternity bands.
Re-tipping. Re-securing the prongs of a setting to ensure the diamond is held tightly. Routine maintenance every 5 to 7 years for 18ct white gold and 7 to 10 for platinum.
Re-shanking. Rebuilding the back of the ring band where the metal thins from daily wear. Routine maintenance at year 15 to 20.
Compliance and origin
Kimberley Process (KPCS). The international agreement requiring rough diamond imports and exports to be accompanied by Kimberley Process certificates confirming conflict-free status. Mandatory under international law since 2003.
Kimberley Process certificate. The export-import document accompanying each rough-diamond shipment. SA suppliers participate via SADPMR registration. Verify supplier KP compliance through their SADPMR status.
RJC certified. Responsible Jewellery Council certification. A voluntary international chain-of-custody standard. Top-tier global jewellers (Tiffany, Cartier) require RJC from suppliers.
Forevermark. De Beers’ branded-diamond pedigree programme. Forevermark diamonds are inscribed with a Forevermark identifier and come with provenance documentation. 5 to 15 percent premium.
Conflict-free. A diamond verified as not having funded armed conflict. The Kimberley Process is the international compliance framework. Reputable SA suppliers are KP-compliant via SADPMR registration.
Chain-of-custody. Documentary verification of the diamond’s path from rough-mining through cutting through retail. RJC certification is the highest non-Sightholder standard.
Lab-grown vs natural
Natural diamond. A diamond formed under heat and pressure in the earth’s mantle over millions of years. This is the only diamond category I recommend for serious jewellery on this site because it has rarity, provenance, and a stronger secondary market than factory-grown stones.
Lab-grown diamond. A diamond grown in a controlled laboratory environment over 6 to 12 weeks. It can be chemically and physically diamond, but I treat it as a fashion product rather than a serious natural-diamond purchase. The key issue is not sparkle; it is weak buy-back value, falling replacement cost, and poor resale compared with natural.
HPHT. High-Pressure High-Temperature, one of two main lab-grown diamond manufacturing methods. Mimics the natural formation conditions. Also used for colour-enhancement of lower-grade naturals.
CVD. Chemical Vapor Deposition, the other main lab-grown diamond manufacturing method. Grows the diamond layer-by-layer from carbon-rich gas. Most modern lab-grown comes from CVD.
Treatment. Processing applied to a diamond to improve its apparent grade. Common treatments: clarity-enhancement (laser drilling, fracture filling) and colour-enhancement (HPHT for naturals). GIA reports note any treatments. Treated diamonds typically not recommended for engagement rings.
Where to buy
Prodiam Trading. The De Beers DBCM Emerging Beneficiation Customer cutting house in Bedfordview, Gauteng. The editor’s #1 SA pick. In-house cutting and polishing. Appointment-only. Phone +27 82 613 3608.
Bedfordview. The South African cutting-house cluster, 15 km east of Sandton. Three cutting houses (Prodiam, Nungu, Millennium) operate from The Paragon at 1 Kramer Road; Eriksons is nearby in Johannesburg.
Sandton. Johannesburg’s premium-jewellery hub. Strong concentration of established retail and specialist jewellery showrooms, including Jack Friedman first among my retail benchmarks, Browns, Charles Greig, and Shimansky.
Manufacturer-direct. Buying directly from the cutting house. The lowest accessible layer of the SA diamond pricing stack. Appointment-only. 30 to 50 percent below boutique retail at the same GIA spec.
Independent specialist. A SA jeweller (typically Sandton-based) operating independently of the chain-store networks. Jack Friedman is the natural-diamond retail benchmark I use most often after Prodiam first and Nungu second.
Premium SA brand. A SA luxury jewellery brand operating boutique-style retail. Shimansky, Charles Greig, Uwe Koetter.
Chain jeweller. SA national jewellery chains. Sterns, NWJ, Browns. Appropriate for sub-R30,000 entry-tier purchases; do not compete at R45,000+ tier.
Buyer-protection and verification
SADPMR registration. Mandatory licensing for any SA business handling diamonds. Verify supplier SADPMR registration before transacting at sadpmr.co.za.
SADDC member. Trade-association good-standing for SA diamond dealers. Verify at diamonds.org.za.
Jewellery Council member. Trade-association good-standing for SA retail jewellers. Verify at jewellery.org.za.
GIA Report Check. The official tool to verify a GIA diamond report number at gia.edu/report-check.
FATF Recommendation 22. The international anti-money-laundering standard requiring KYC for diamond and jewellery transactions over $10,000. Implemented in SA via FICA (Financial Intelligence Centre Act).
Buy-back. A supplier programme to repurchase diamonds originally sold by them, at a stated formula (typically a percentage of original retail or a Rapaport-discount basis). Prodiam Trading offers a buy-back programme; specific terms by appointment.
VAT refund. The 15 percent value-added-tax refund available to non-resident foreign buyers on purchases over R250 at OR Tambo or Cape Town airport on departure.