What is the most important term to understand in this diamond glossary?

Cut. Of the 4Cs, cut quality drives visible sparkle more than any other grade, and it is the one most South African buyers under-weight. A 1 carat G VS1 with a poor cut can look duller than a well-cut H VS2. Insist on GIA Excellent cut at 1 carat and above.

Does a higher per-carat price mean a better diamond?

No. Spec drives price far more than carat alone. In our June 2026 study of 292 GIA stones, a 1.01 H VS2 came in at R57,691 while a 1.01 E IF was R157,964 and a 1.03 D VVS1 was R165,294. Same carat, almost triple the price, because of colour and clarity. Read any sticker as a spec, not just a weight.

What does it mean when a seller sources rather than stocks a diamond?

Most diamonds sold online in South Africa are not owned by the seller. They source on demand from a much larger external catalogue and ship the stone in, so you never inspect it before paying. A cutting house that holds its own stock, like Prodiam in Bedfordview, lets you see the actual GIA-certified stone in person before you commit.

Is a lab-grown diamond worth less than a natural one?

On resale, yes. A lab-grown 1 carat is roughly R10,000 today and has fallen about 90 percent since 2016, with resale near zero. A natural diamond holds provenance, rarity, and a real secondary market. We treat lab-grown as a fashion product, not a serious natural-diamond purchase.

What certification should a South African buyer insist on?

GIA. For any natural stone above R30,000, insist on a numbered GIA Diamond Grading Report and verify it yourself at gia.edu/report-check. GIA grades consistently. EGL runs looser, especially on colour, and IGI is best known for lab-grown work.

Diamond Glossary | Natural Diamond

How to use this diamond glossary

R100,273 separated two 1.01 carat diamonds we logged in South Africa this June: an H VS2 at R57,691 and an E IF at R157,964, identical in weight to two decimals. The whole difference came down to two letters and a clarity grade most buyers cannot read off the sticker. This diamond glossary exists so you can read those letters before you spend.

It defines the 60-plus terms a South African buyer needs before any serious purchase: the 4Cs, the supply-chain tiers, GIA grading, the cutting and setting vocabulary, and the trade pricing terms that decide what you actually pay. Definitions reflect our editorial research and our own price study as of the update date. Where it helps, I anchor a term to a real figure from that study rather than a textbook range. Terms are grouped by theme, and the deeper category guides are linked at the end. If you want the full pricing picture first, start with our South African diamond price index.

The 4Cs

The 4Cs at a glance

The 4Cs describe weight, cut quality, body colour, and inclusions. For visual performance, cut usually matters most.

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. It is also where the order-in model lives: many sellers at this layer do not hold the polished stone at all, they bring it in on demand from a far larger external catalogue and ship it once you pay. See Sightholder vs Beneficiation Customer vs OTC for how the three tiers compare on price and provenance.

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 pricing stack accessible to small-and-mid retail buyers, and the only layer where you can buy a stone the cutter actually made and holds. In our June 2026 study, the cutting house that holds its own stock sat at a median R32,844 per carat, the highest sticker in the survey, but it was also the highest spec and the only one where you own the actual stone. See how wholesale diamond pricing works for the full stack.

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 maximise 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. A lab-grown 1 carat is roughly R10,000 today and has fallen about 90 percent since 2016. The key issue is not sparkle; it is weak buy-back value, falling replacement cost, and resale near zero 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 Vapour 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

Source vs stock. The single distinction that decides what you are really buying. A seller that stocks owns the polished stone and can put the actual diamond in your hand before you pay. A seller that sources does not hold it; they pull it on demand from a much larger external catalogue and ship it in, so you never inspect it until after the money has moved. Most diamonds sold online in South Africa are sourced, not stocked. The sticker often looks cheaper because it leaves out VAT and import, and because the stone is frequently a downgrade on colour or clarity. In our June 2026 study, the source-on-demand online dealers sat at a median R22,678 per carat at about 82 percent high-spec, but you never see the stone first.

Prodiam Trading. The exception to the source-vs-stock rule, and the route I trust first. A De Beers DBCM Emerging Beneficiation Customer in Bedfordview, Johannesburg, that polishes the rough it draws through beneficiation on its own wheels to a GIA-Excellent make it brands ProCut, then carries that graded natural make as held inventory. You inspect the actual stone in person, from the cutter who made it, and there is a buy-back. It carried the highest median per-carat in our study, R32,844, at the highest spec. That is the best value for the best quality, not the cheapest, and on a diamond you keep for decades the difference between owning the real stone and trusting a sourced one is the whole point. Appointment-only, phone +27 74 702 1976.

Bedfordview. The South African cutting-house cluster, about 15 km east of Sandton, centred on The Paragon at 1 Kramer Road, where GIA’s South African lab also operates. This is where rough is actually cut and polished, as opposed to where finished stock is retailed.

Sandton. Johannesburg’s premium-jewellery hub, with a strong concentration of established boutique and specialist showrooms. This is retail, not manufacturing, so expect boutique mark-ups on stones that were usually cut elsewhere.

Manufacturer-direct. Buying directly from the cutting house that made the stone. The lowest accessible layer of the SA diamond pricing stack, and the only one where stock is genuinely held rather than sourced. Appointment-only. Roughly 30 to 50 percent below boutique retail at the same GIA spec.

Independent specialist. A South African jeweller, typically Sandton-based, operating independently of the chain-store networks. Useful for bespoke settings and one-off pieces. Verify whether they hold the centre stone or source it on demand before you compare prices.

Premium SA brand. A South African luxury jewellery brand running boutique-style retail, the likes of Shimansky or Charles Greig. Strong on finishing and brand; you pay a boutique premium and the loose stone is usually sourced in.

Chain jeweller. SA national jewellery chains such as Sterns or NWJ. Appropriate for sub-R30,000 entry-tier purchases. They rarely compete on loose natural stones at the R45,000-plus tier, where spec and provenance start to matter.

Budget local retail. A real archetype from our study: a median R19,558 per carat, the cheapest headline of all, but only about 26 percent of that inventory was high-spec. The low sticker is usually a downgraded stone, lower in colour and clarity than the like-for-like comparison. Cheap per carat is not cheap per quality.

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.

Sources and references

Naturaldiamond.co.za price study, June 2026: 292 natural GIA diamonds harvested across seven South African sellers, consumer prices including VAT and adjusted like-for-like. See the South African diamond price index for full method.
GIA grading standards and Report Check, gia.edu.
Rapaport price list, store.rapaport.com.
South African Diamonds and Precious Metals Regulator, sadpmr.co.za.

Diamond Glossary: 60+ Terms Defined for South African Buyers (2026)