We buy diamonds in Miami at live Rapaport-basis pricing. GIA-graded loose diamonds, mounted diamonds, antique cuts (old mine, old European, rose), fancy color diamonds with cert, and natural diamond jewelry from estates. On-site GIA-trained grading in our Surfside showroom, transparent math, no mystery numbers. Same-day cash for transactions under $25,000, same-week wire for larger.
Most Miami diamond buyers price opaquely. A pawn shop or “Cash for Diamonds” storefront will look at your GIA cert, write down a number, and pocket the spread between what they paid you and what they sell the stone for. CJW prices every stone off the live Rapaport sheet, shows you the percentage, and explains the adjustments (fluorescence discount, table outside spec, deep pavilion, certificate vintage) so you can verify the math yourself. That is the wedge.
Not sure how to read your GIA cert or what the 4 Cs mean for your price? Read our Diamond Certification Guide for a full breakdown of GIA/AGS/HRD/GCAL labs, the 4 Cs, fluorescence impact on price, how to read a diamond report, and why cert vintage matters.
What Diamonds We Buy in Miami
GIA-Certified Loose Diamonds
The cleanest category for both seller and buyer. Round brilliant, oval, cushion, emerald cut, princess, radiant, pear, marquise, asscher, and heart shape stones graded by GIA. We also accept current AGS, HRD, and GCAL certs. Priced off the live Rapaport sheet with cert in hand. Typical payout: 50 to 65 percent of dealer wholesale, with adjustments fully explained.
Mounted Diamond Jewelry
Engagement rings, anniversary bands, tennis bracelets, pendants, and earrings. For signed pieces (Cartier, Tiffany, Harry Winston, Van Cleef) we evaluate the maker premium on the setting separately from the stone value. For unsigned settings we typically remove the stone (where it benefits the seller) and price it separately, then value the setting at melt-plus-workmanship. The seller decides.
Antique-Cut Diamonds
Old mine cut, old European cut, and rose cut diamonds from Georgian, Victorian, Edwardian, and Art Deco era jewelry. These cuts have different proportions than modern round brilliants and a different market. Valued at collector premium when craftsmanship and condition support it. We never price an old mine cut as if it were a modern round, which is what melt-focused buyers do.
Fancy Color Diamonds
Natural fancy yellow, pink, blue, brown, green, gray, and orange diamonds. Cert from GIA strongly preferred and typically required for fancy color. Treated stones (HPHT, irradiated) are bought but priced and disclosed separately from natural color. Fancy color pricing is independent of the Rapaport sheet and depends on the specific stone, the cert grade, and current market for that color.
Lab-Grown Diamonds
We buy lab-grown diamonds, priced separately from natural. Lab-grown wholesale prices have fallen sharply over the past several years and continue to compress. We disclose the natural-vs-lab pricing difference clearly so you understand what your stone is worth in today’s market. Cert verification (or testing on site) confirms whether a stone is natural or lab-grown.
Uncertified Diamonds
Loose diamonds without current certs are graded on site by our GIA-trained staff. For stones large enough to justify it (typically half-carat and above), we recommend submitting to GIA for a current cert before sale; the cert almost always pays for itself in the higher offer it commands. We can coordinate that submission for stones above a meaningful threshold.
How CJ William Compares to Other Miami Diamond Buyers
| Buyer Type | GIA-Graded Loose | Mounted & Antique | Pricing Transparency |
|---|---|---|---|
| Pawn shop | 30 to 45 percent of wholesale | Melt only on setting, low offer on stone | Opaque, no math shown |
| Mall-style “Cash for Diamonds” | 25 to 40 percent of wholesale | Often refuses antique cuts | Opaque |
| Auction house consignment | 40 to 60 percent of hammer, 60+ days, plus commission | 40 to 60 percent of hammer, 60+ days | Depends on hammer price (uncertain) |
| CJ William Surfside | 50 to 65 percent of Rapaport wholesale | Collector premium on antique, maker premium on signed | Live Rapaport sheet, math shown |
How the Process Works
- Initial contact. Call (347) 510-0668, WhatsApp, the inquiry form, or walk into the Surfside showroom at 9573 Harding Avenue. For larger stones and collections we travel.
- Cert verification or on-site grading. If you have a GIA, AGS, HRD, or GCAL cert, we verify the cert matches the stone (laser inscription check, weight, measurements). If uncertified, our GIA-trained staff grade on site. You watch the process.
- Live Rapaport-basis pricing. Stone graded, Rapaport sheet pulled up live, adjustments explained (fluorescence, table, depth, cert vintage). Final offer expressed as a percentage of Rap, with the math shown.
- Written offer. Per-stone line items showing weight, color, clarity, cut grade, fluorescence, cert source and number, Rap basis, adjustments, and final offer. Time to review.
- Payment. Same-day cash for transactions under $25,000 (with ID and Form 8300 for cash above $10,000), same-week wire for any size, USDC or USDT available for digital-asset preferred clients.
- Documentation. Bill of sale showing every stone individually with cert references where applicable. Suitable for CPA, IRS, estate probate, and insurance records.
Selling Diamonds From an Estate or Collection
Estate diamonds and full diamond collections are a specialty of CJ William. Single high-value certified stones, full diamond suites, antique-cut estate diamonds, and fancy color collections regularly come through our Surfside showroom and our traveling appraisal service. We coordinate directly with the estate attorney, executor, fiduciary, or trustee, provide written valuations suitable for probate and IRS step-up basis documentation, and structure payment to fit the needs of the estate account. This service is part of CJ William’s broader luxury asset liquidation practice. See also We Buy Estate Jewelry in Miami for the broader estate process.
Frequently Asked Questions
What diamonds does CJ William buy in Miami?
GIA-graded loose diamonds (and stones graded by AGS, HRD, or GCAL), mounted diamond jewelry, antique-cut diamonds (old mine, old European, rose), fancy color diamonds with cert, and natural diamond jewelry from estates. We also buy lab-grown diamonds, priced separately at current lab-grown market levels.
How is your diamond offer calculated?
For GIA-graded loose diamonds we typically pay 50 to 65 percent of dealer wholesale (Rapaport sheet, current week, adjusted for fluorescence, table, depth, and cert vintage). For uncertified loose we grade on site and typically pay 45 to 60 percent of estimated wholesale. For mounted diamonds we remove the stone where it benefits the seller and price separately. For antique cuts we apply collector premium. For fancy color we price off the original cert.
Why is CJ William different from other Miami diamond buyers?
Most local buyers price opaquely. A pawn shop will look at your GIA cert, mumble a number, and pocket the spread. CJW prices off the live Rapaport sheet, shows you the math, and explains every adjustment so you understand exactly why your stone is priced where it is.
Do you buy uncertified diamonds?
Yes. We grade uncertified diamonds on site using GIA-trained staff. For larger stones we recommend submitting to GIA for a current cert before sale, as the cert typically pays for itself in the higher offer.
Do you buy diamond engagement rings?
Yes. We typically remove the stone (where it benefits the seller) and price separately from the setting. For signed engagement rings (Cartier, Tiffany, Harry Winston) we evaluate maker premium on the setting as well. The full ring stays intact if the seller prefers.
What about lab-grown diamonds?
We buy lab-grown diamonds at current market. Lab-grown wholesale prices have fallen sharply in recent years and continue to compress. We disclose the natural-vs-lab pricing difference clearly so you understand what your stone is worth in today’s market.
Do you buy antique-cut diamonds?
Yes. Old mine cut, old European cut, and rose cut diamonds from Georgian through Art Deco era jewelry are valued at collector premium when condition and craftsmanship support it. These cuts are not modern round brilliants and should never be priced as if they were.
Can I sell diamonds to CJ William remotely?
Yes. Send clear photos of the stone and the cert (if certified) for an initial range. For transactions over $5,000 we provide a fully insured FedEx overnight label. On receipt we verify the stone matches the cert (or grade it if uncertified), then wire payment the same day.
Ready to Sell Your Diamonds?
Bring the stones to the Surfside showroom for live Rapaport-basis pricing the same visit. Out of state, or selling a full collection? Send photos for an initial range, ship insured, or we travel for collections over $250,000.
This page is part of Luxury Asset Liquidation in Miami. See also We Buy Estate Jewelry, We Buy Gold, We Buy Silver, and We Buy Platinum in Miami. CJ William, 9573 Harding Avenue, Surfside, FL 33154. Sunday through Friday, 11:00 AM to 5:30 PM. Invoicing entity: David and Sons Watches LLC.