The most common type of wire paper clip still in use, the Gem paper clip, was never patented. According to the American expert on technological innovations, Professor Henry J. Petroski, the earliest documentation of the modern paperclips existence is an 1894 advertisement for “Gem Paper Clips”. In 1904 Cushman & Denison registered a trade mark for the “Gem” name in connection with paper clips. The announcement stated that it had been used since March 1, 1892, which may have been the time of its introduction in the United States. Paper clips are still sometimes called “Gem clips”, and in Swedish the word for any paper clip is “gem”.
Norwegian, Johan Vaaler, has erroneously been identified as the inventor of the paper clip. He was granted patents in Germany and in the United States (1901) for a paper clip of similar design, but less functional and practical, because it lacked the last turn of the wire. Vaaler probably did not know that a better product was already on the market, although not yet in Norway. His version was never manufactured and never marketed, because the superior Gem was already available.