Broad Street Gold
Step by step

How to test a piece of gold jewelry

Work from the least invasive check to the most. Each step narrows what the metal can be.

  • Non-destructive first
  • Acid last
  • Five minutes total
  1. 1

    Read the hallmark under magnification

    Look for 10K, 14K, 18K, 375, 585, 750 or 999, plus an assay or maker mark. Crooked spacing, soft edges or a stamp that sits on top of plating are warnings, not proof of anything on their own.

  2. 2

    Try a strong magnet

    Gold is not magnetic. A pull means a ferrous core or clasp. No pull means very little on its own — most fake bases are non-magnetic too — so never stop here.

  3. 3

    Weigh and measure

    Compare weight against the size of the piece, and for coins and bars against the mint specification. Off-spec thickness or a light weight for the volume points at a lower-density base metal.

  4. 4

    Use an electronic tester

    A conductivity tester reads below the surface without marking the piece. This is the step that catches heavy plating and gold-filled stock that passes a surface acid test.

  5. 5

    Confirm with acid on a streak

    Rub the piece on a test stone and apply graded solutions from low karat upward. The streak that survives tells you the karat. Do this on an inconspicuous area, wear eye protection, and neutralise afterwards.