Bizak & Co. · Miami · Since 1996

Jewelry Guides & Expertise

Thirty years at the bench, poured into plain-English guides — so you can buy, sell and care for fine jewelry with confidence.

30 Years in the TradeWritten by a Working Jeweler

All Guides

What Is Estate Jewelry?

Estate vs. vintage vs. antique — and why pre-owned is the smart way to buy. Read the guide →

Jewelry Eras: Georgian to Mid-Century

How to place a piece in time — motifs, metals and what collectors pay for. Read the guide →

Jewelry Hallmarks Explained

585, 750, 925, PLAT — read the tiny stamps and spot the fakes. Read the guide →

Jewelry Glossary

Pavé, vermeil, old mine cut — the trade’s language in plain English. Read the guide →

Gold Karats Explained

10K vs. 14K vs. 18K — purity, durability and value. Read the guide →

Platinum vs. White Gold

Two white metals, very different personalities — which is right for you. Read the guide →

Diamond Buying Guide

The 4 Cs without the sales pitch — how to buy smart. Read the guide →

Colored Gemstone Guide

Sapphires, rubies, emeralds — what drives beauty and price. Read the guide →

Designer & Signed Jewelry

Cartier, Tiffany, David Webb — why a signature multiplies value. Read the guide →

Vintage Watch Buying Guide

Authentication, condition and value in pre-owned watches. Read the guide →

How Much Is My Jewelry Worth?

Insurance, resale, melt — the four values every piece has. Read the guide →

Jewelry Appraisals

Written appraisals by mail, nationwide — process and pricing. Read the guide →

Authenticity & Trust

How we verify what we sell — and what we appraise. Read the guide →

Prefer a Straight Answer?

Skip the reading — send photos of your piece and we’ll tell you what it is and what it’s worth, in writing. Since 1996.