Assay Jewelry
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Rare gems. Rare watches. Real knowledge. ASSAY is a curator of certified colored gemstones, diamonds and luxury watches with provenance.
We source pieces you won't find anywhere else — and we've been doing it since 1983. GIA Graduate Gemologist on staff.
06/11/2026
Vintage Rolex Cellini 3807 in 18K gold with a champagne dial and textured bracelet. Clean, warm, and quietly elegant.
POTC2625W- available for direct purchase on our website while supply lasts
One of the rarest sapphire colors in the world. The legendary Padparadscha Sapphire. Certified and unheated from Sri Lanka. 🇱🇰
It’s now sold and no longer available.
06/10/2026
Vintage Omega De Ville in 18K gold with a matching gold bracelet and classic champagne dial. Elegant, understated, and a beautiful example of timeless Swiss watch design.
POTC2008W- available for direct purchase on our website while supply lasts
How to tell if you have lab grown or a natural diamond
Use a loupe and check the girdle.
• Many lab grown diamonds have a laser inscription
• Most start with “LG” or say “Lab Grown”
• Natural diamonds may have a GIA inscription or no inscription at all
It’s not foolproof, but it’s one of the fastest checks you can do yourself.
06/09/2026
Cartier Tank Française Large 28mm with a two tone case and bracelet, silver guilloché dial, bold Roman numerals, and automatic movement. A timeless design that remains one of Cartier's most recognizable watches.
#3066-available for direct purchase on our website while supply lasts
06/09/2026
Rolex Daydate 36mm in 18K gold with a fluted bezel, champagne tapestry dial, and Presidential bracelet. A classic for a reason.
POTC2632W- available for direct purchase on our website while supply lasts
This green isn’t just rare… it’s elite. 💚
Imperial jadeite jade is one of the most expensive gemstones on earth.
And it’s not just about color.
It’s the combination of:
- Rich green
- Glowy luster
- Smooth texture
- Perfect uniformity
- Most importantly, untreated.
Almost no jade has all of these at once.
That’s why it’s one of the most desired gemstones in the East.
SKU - GA0417
06/07/2026
Vintage Bucherer in 18K gold with a clean dial and brown leather strap. Simple, classic, and quietly elegant
06/06/2026
Vintage Rolex Thunderbird with a two tone case, warm dial, and that bold Turn-O-Graph bezel. Classic Datejust feel with a little more personality.
How To Test If Gold Is Real At Home
A $30 acid test kit can tell you whether your gold is real and help estimate its purity.
• Scratch the metal onto the testing stone• Apply the corresponding acid
• If the gold mark remains, the metal is that purity or higher
• If it disappears, it’s lower purity or not gold at all
Simple, inexpensive, and one of the fastest ways to screen gold before deeper testing.
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Address
169 East Flagler Street
Miami, FL