STG Silver Mark: What STG Means on Silver and Jewelry

STG on silver is an abbreviation of STERLING: the maker is saying the piece is sterling silver, which means at least 925 parts pure silver in every 1,000, the rest usually copper. It is the same claim as STERLING or 925, written in a shorter form.

You will most often see it as STG, STG SIL, STG SILVER or S. SIL, usually next to a maker's initials. An Australian silver-buying reference lists STG, STG SIL and S. SIL as the forms found on older Australian pieces, and an Australian vintage jewellery dealer describes STG SIL and STG SILVER as distinctly Australian marks.

Australia never adopted a compulsory national hallmarking system like Britain's, and there is still no legal requirement to mark silver or gold there. Australian silversmiths had no assay office to send work to, so each workshop stamped its own initials and its own word for sterling. STG and STG SIL were among the most common choices.

Some makers borrowed the look of British marks. Hardy Brothers, established in 1853, combined H.Bros with British-style symbols, and the Melbourne firm Stokes & Sons used a wheatsheaf. Pieces by J.M. Wendt, established in Adelaide in 1854, are described as rare. None of these marks were tested by an independent office, which is the key difference from a British hallmark.

A documented example: a jewellery casket stamped E.H. STG. SILVER is attributed by Chineur Antiques to Edwin Harrop, a Sydney silversmith who worked until his death in 1894, with the business continued by his son until 1915.

Because STG is a maker's claim rather than a tested hallmark, treat it as the start of the check, not the end.

• Look for a maker's mark beside it. STG with initials is the normal Australian pattern; STG with nothing else, on a cheap modern piece, deserves more caution.
• Look at worn edges. Plated pieces show a yellow or pink base metal where the plating has rubbed through on high points and rims.
• Check for plate words. EPNS, EP, A1 or Quadruple Plate anywhere on the piece means it is plated, whatever else is stamped. See silver plate company marks.
• Ask a jeweller for an acid or XRF test. A jeweller's acid test turns creamy white on sterling and green on plated or base metal; assay offices use X-ray fluorescence, which does not mark the piece.
• Tarnish is not a sign of a fake. Sterling darkens normally in contact with skin and air.

• STG, STG SIL: sterling claim, usually Australian, not independently tested.
• STERLING or 925 alone: sterling claim by the maker; in the US the FTC standard requires at least 925/1,000, with a tolerance of 4 parts per 1,000 for unsoldered articles. See 925 and coin silver.
• 925 with a lion passant and an assay office mark: a British hallmark, independently tested. See British sterling hallmarks.
• COIN: older American silver, at least 900/1,000 under FTC rules.
• 800 or 830: continental European silver, below sterling. See 800 and 830 silver.
• EPNS, EP, A1: silver plate over base metal.

People asking about the five standard silver marks usually mean the British set, which is what STG was imitating in spirit:

• Maker's (sponsor's) mark: initials in a shield.
• Standard mark: the lion passant for sterling.
• Assay office or town mark: for example the leopard's head for London.
• Date letter: a letter that changes every year.
• Duty mark: the monarch's head, struck from 1784 to 1890 to show tax had been paid.

An STG piece has, at most, the first of these. To read a full British set, use English silver date letters.

If the piece is plain sterling with no collectable maker or design, its floor value is the silver in it. Weigh it in grams, multiply by 0.925 for the pure silver content, divide by 31.1035 to convert to troy ounces, and multiply by the day's silver spot price.

Buyers pay less than that melt figure. MeltValue.com says the strongest buyers pay around 70 to 80% of melt on sterling flatware and scrap, and US Pawn wrote in April 2025 that pawn shops typically offer 30 to 60% of the market value of silver. Get more than one offer, and ask whether a piece has maker or design value before selling it by weight, because a named maker is worth more than the metal.