Bizak & Co. · Miami · Since 1996
Bizak & Co.Jewelers · Est. 1996

Sell Diamonds · Nationwide, by mail

Sell your diamonds — read by a gemologist, priced on demand.

Loose or set, certified or not — mail your diamonds in with free insured shipping and a trained gemologist grades every stone on the 4Cs. Written offer at true market demand, same-day payment, or your diamonds back free.

Graded on the 4Cs Certified or not Insured FedEx both ways Same-day payment

Diamonds we buy

From a single loose stone to an inherited estate — with paperwork or without.

Loose Diamonds

Single stones and parcels, any shape — round, princess, emerald, oval, cushion and more.

Diamond Rings

Engagement rings, solitaires and set pieces. We value both the stone and the mounting.

Certified & Uncertified

GIA and other lab reports welcome — but our gemologist reads the stone either way.

Estate & Inherited

Full collections and older diamond jewelry, every era and every cut.

Certificates we accept

Send whatever paperwork came with the stone. Every report is read — and every stone is still graded in person.

What a report does

  • Confirms the grade a buyer would otherwise have to take on trust
  • Speeds things up — less back and forth about the stone
  • Helps most on larger stones, where a single grade moves real money
  • If the stone is laser-inscribed, we match the number on the girdle to the report

What it does not do

  • It is not required — an uncertified stone still gets a firm written offer
  • It does not replace grading in person: standards differ between labs, so we read the stone ourselves either way
  • An old appraisal for insurance is not a grading report and is not a selling price — it is a replacement figure
  • A report does not set the offer; the market for that exact stone does

Not sure what your paper actually says? Start here: HRD vs GIA certifications explained → We also identify natural versus laboratory-grown stones as part of grading, and we tell you which one you have — the two are worth very different amounts on the resale market.

Loose or still in the setting

Both are welcome. Send the piece exactly as it is — there is no need to have anything unset first.

Loose stones

  • Weighed on a scale and measured, so carat weight is exact
  • Graded face-up and through the pavilion, the way a buyer sees it
  • Parcels of small stones are welcome — send the whole lot together

Stones in a mounting

  • Graded in the setting: prongs hide part of the stone, so clarity and color are read as a tight range
  • Weight is calculated from measurements when the stone cannot be removed
  • The mounting is valued too — metal, signature and any side stones
  • Nothing is unset, altered or dismantled before you accept the offer in writing
Value my diamond on WhatsApp A photo of the stone and of the report, if you have one, is enough to start.

How your diamond offer is built

Every stone is graded in person by a trained gemologist — not weighed and guessed. We read it on the 4Cs: cut, color, clarity and carat.

From there, the offer reflects current wholesale and resale demand for that exact type of stone — because two diamonds of the same weight can be worth very different amounts. If you have a GIA or other certificate, it confirms the grade and can speed things up, but it's never required.

You see the full offer in writing before you decide. Accept, and you're paid the same day by bank transfer. Decline, and your diamonds come back to you free and fully insured.

Confused by the paperwork? Read our guide: HRD vs GIA certifications explained →

How it works

01

Request a kit

Tell us what you have. We email a prepaid, fully-insured FedEx label — you pay nothing to ship.

02

Drop it at FedEx

Pack it and drop it off. Insured door to door through IFS (In4Sure), signature required.

03

We grade & offer

A gemologist reads each stone on the 4Cs and emails a written offer with the reasoning.

04

Paid same day

Accept and you're paid the same day by bank transfer — or everything ships back free.

How your diamond travels, and how it comes back

The same carrier and the same cover in both directions. You never pay to ship, whether you sell or not.

A prepaid FedEx label, by email

Tell us what you have and we email a prepaid, fully insured FedEx label with simple packing instructions. It arrives by email — there is no box to wait for — and it ships on our account, so you pay nothing.

Drop it at any FedEx location

Print the label, pack your diamond and hand the package in at any FedEx location. From that moment it is tracked door to door, with a signature required at every handoff. Your package is never left on a doorstep. Not sure how to pack a loose stone? Our step-by-step packing guide walks through it.

Insured to full value, both ways

Cover runs through IFS (In4Sure), a dedicated jewelry insurer — not a carrier’s flat default that stops at a token amount. Your diamond is insured for its full value on the way to us and on the way back.

Decline, and it ships back free

Say no to the offer and the exact stones and pieces you sent come back to you, free and fully insured on the same cover. No restocking fee and no fee for our time — and nothing is unset, altered or dismantled before you accept in writing.

If you are sending a loose stone, keep it in its stone paper or a small sealed envelope inside a rigid box, so it cannot work loose in transit. Send the lab report with it if you have one — and if you do not, send the stone anyway. Our gemologist grades it either way.

Frequently asked questions

Do you buy uncertified diamonds?

Yes — certified or not. Our gemologist grades the stone in person, so a certificate isn't required to get a firm offer.

Do I need a GIA certificate to sell my diamond?

No, but it helps. A GIA or other lab report confirms the grade and can speed things up. We read the stone on its 4Cs either way.

How do you price a diamond?

On the 4Cs — cut, color, clarity and carat — plus current wholesale and resale demand for that type of stone, assessed by a trained gemologist. You see the offer in writing.

Do you buy diamond rings and estate jewelry?

Yes — loose or set, single stones or full estates and inherited collections. We value both the diamonds and the piece.

How and when am I paid for my diamond?

The same day you accept the offer, by bank transfer. No consignment and no waiting.

Is my diamond insured when I mail it?

Yes. You ship on a prepaid, fully insured FedEx label through IFS (In4Sure), tracked, with signature required, both ways.

What is the fastest way to reach you?

WhatsApp, at +1 786-907-8883. Send a photo of what you have and we will tell you what we can already see, and what we would still need in order to make an offer. If you would rather start in writing, request a free shipping kit from the home page. Either way the valuation is free and there is no obligation.

Ready to sell your diamonds?

Request a free, insured shipping kit — no obligation. See your written offer before you decide.