matte proof 上市 Deposited
One given its uniformly granular or dull surface at the Mint by pickling in acid; a European 1890s technique adopted at the Philadelphia Mint in 1907, but abandoned before 1936.
- Breen Encyclopedia
One given its uniformly granular or dull surface at the Mint by pickling in acid; a European 1890s technique adopted at the Philadelphia Mint in 1907, but abandoned before 1936.
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