What actually sets diamond carat size chart in South Africa
Polished diamonds trade globally in US dollars, so every South African price carries two stories: the stone's quality profile and the rand. On top of that sit the certificate, the cut quality, market demand for that size and shape, and the route the stone is travelling: retail purchase, insurance replacement, or resale. A single headline number for diamond carat size chart hides all of it, which is why two honest answers to the same question can differ.
The forces that move a specific stone's number
Quality first: the 4Cs set the band, but the make sets the life. Two stones with identical paper can differ in light return, and the better make earns more. Documentation second: a GIA-certified stone is more liquid than the same stone uncertified, because the buyer carries less risk. Shape and size third: round brilliants are the most liquid shape, and demand concentrates around popular weights, with price stepping up at the thresholds buyers search for. Currency fourth: when the rand weakens against the dollar, replacement costs in rand drift upward even when the global market is flat. Route last and most misunderstood: an insurance valuation estimates what replacing the stone at retail would cost, while resale happens in a market that buys below retail. Both numbers are real. They answer different questions.
Why online price answers disagree with real offers
Online estimates average a market; an offer prices one stone, inspected, on a specific day, through a specific route. Sellers anchored to an insurance valuation feel insulted by honest resale offers, and buyers anchored to a discount listing distrust honest retail quotes. The protection against both is the same: insist that any number comes with its method: what was inspected, what reference data was used, and which route the number assumes.
When Prodiam is the right next step
Ask Prodiam to review carat, measurements, and spread together. 4Cs.co.za is published by Prodiam Trading CC: the education is free, the disclosure is permanent, and the specialist conversation is there when a real stone needs one. Bring the certificate or report number, photos in plain light, and any invoices or valuations, and the conversation starts from evidence instead of guesswork.
Decision table
Use the details, not a shortcut.
| Factor | Pushes the number up | Pushes the number down |
|---|---|---|
| Certificate | GIA report matching the stone | No report, or a lenient lab's letters |
| Make | Strong cut, light return, balanced spread | Hidden depth, dullness, poor symmetry |
| Shape and size | Liquid shapes and sought-after weights | Slow shapes, in-between weights |
| Currency | Weaker rand lifts replacement cost | Stronger rand softens it |
| Route | Retail replacement context | Fast-cash and scrap-level routes |
Direct answers
Common questions
Why can nobody tell me diamond carat size chart over the phone?
Because the honest inputs are missing: the certificate details, the stone's condition and make, and the route. A figure given without those is a guess dressed as an answer.
Is my insurance valuation what my diamond is worth?
It is what replacing it at retail might cost, which protects you in a claim. Resale happens in a different market and prices differently. Knowing both numbers is what makes you informed.
Do diamonds hold their value?
Quality certified stones hold value better than mass commercial goods, but the buy-retail-sell-resale gap is real everywhere. The stones that fare best combine strong cut, certification, and liquid sizes.
When is the right time to sell?
When you have the paperwork assembled, the stone professionally seen, and a route chosen on purpose. Market timing matters less than route quality for a single private stone.