One concave line represented 140/1000 fineness, a straight one 150 and a convex one 160.
For example, a Diana head within a frame made in the shape of a 5-petal flower represented 5x160 = 800 thousands fineness, a local silver standard commonly used in eating forks and spoons.
The date letters below show the background shape for silver.
The same letters were used for Gold, which has been marked in Birmingham since 1824, but with a background of a square with cut corners.
The head was encircled by a frame, optionally composed of convex, concave and straight lines.These five nations have, historically, provided a wealth of information about a piece through their series of applied punches.It should be noted that since 2015 visually identical UK Hallmarks are being struck in India and Italy by sub-offices of Birmingham & Sheffield Assay Offices respectively: London assay office hallmarks on the back of a waiter, or small square salver.If there is ever a question about the content of a piece of jewelry, the manufacturer can be traced using the hallmark stamped on the piece....US law requires a maker's mark in the form of a hallmark or registered trademark in addition to the quality mark if the goods are quality marked.