The line “PT950 total weight 2.9169g, diamond 1/0.22ct, main stone VS/F-G round diamond” gives useful identification clues, but it is not a complete appraisal. Taken literally, it describes a platinum-alloy ring with one 0.22 ct round diamond. The brand claim and markings still need to be checked against the item and its documents.
Precise reading of the marks
- PT950: platinum alloy with about 95% platinum content. The London Assay Office hallmark guide lists platinum 950 among recognised finenesses.
- Total weight 2.9169g: likely the finished ring weight, including the diamond and setting.
- 1/0.22ct: commonly denotes one diamond weighing 0.22 carat, or 22 points; confirm the original document’s column headings. The GIA diamond carat-weight guide states that one metric carat is 200 milligrams, so 0.22 ct is about 0.044g.
- VS/F-G round: appears to describe very slightly included clarity and an F–G colour range. It does not specify VS1 versus VS2, cut quality, natural/laboratory-grown origin, treatments or a buyback price. “Round” describes the shape; it is not a cut grade.
What still decides the value
The GIA diamond grading report guide explains why a diamond’s report details matter beyond carat weight: color, clarity, cut, treatments and report number all affect comparison. The Lao Fengxiang official website and Lao Fengxiang after-sales page can help locate official brand service channels, but they do not turn this mark text into a fixed resale amount.
For a metal quote, use the buyer’s stated basis carefully: a pure-platinum price requires multiplying by platinum fineness, while a PT950-per-gram quote already reflects the alloy basis and should not be multiplied by 0.95 again. For a finished-ring sale, the verified diamond report, condition, brand documentation and buyer demand decide whether the offer is above metal value.
A weight calculation, with its limits
If the stated 2.9169g is the complete ring weight and the 0.22 ct diamond is the only non-platinum component, the diamond contributes 0.22 × 0.2 = 0.044g. The remaining alloy would therefore weigh 2.9169 − 0.044 = 2.8729g, equivalent to approximately 2.7293g of fine platinum at 95% fineness. This conditional calculation is useful for checking a quotation’s weight basis; it does not verify the ring, its measured weight or what a buyer will pay.
If the buyer quotes per gram of PT950 alloy, compare that quote against the accepted alloy weight without multiplying by 0.95 again. If the reference price is for pure platinum, compare it against the fine-platinum equivalent and then account for the buyer’s stated deductions. Both calculations exclude a separate diamond offer.
Compare like-for-like ring offers
When comparing a retail replacement, use rings with the same documented metal, diamond origin, approximate stone size and grading basis. Do not compare a new branded setting with a metal-scrap offer as if they were the same product. For resale, ask whether the buyer will keep the ring intact, how the diamond is valued and whether any inspection or removal affects your ability to decline.
Keep a photograph of the complete ring, its hallmarks and documents alongside each quote. The many decimal places in the stated weight do not make a price calculation equally precise: the scale reading, actual composition, stone assessment and transaction terms still need to be established.