Once in a while, there are some common coins with some history behind them which makes them more valuable as they present rare relics of a historical event.
Here is one of those coins, which according to its inscription was taken off the board of the German warship SMS Emden ship, which was destroyed by the Australian cruiser HMAS Sydney and went aground at the North Keeling Island on 9th of November, 1914.
It is known, that the ship has carried coins of German East Africa silver coins and Mexican 8 Reales coins, some of which were turned into medals, other into memorial plaques and a few engraved as memorial pieces at both sides by Australian soldiers and German survivors.
The present piece is one of those coins, which were engraved by Germans and probably taken home:

Engraved Inscription in German: VON BORD S.M.S. "EMDEN" 9. Novbr. 1914 RIFF VON NORD KEELING .
Translated: "Taken off the board of SMS Emden, 9th November 1914,"

SMS Emden ("His Majesty's Ship Emden")was the second and final member of the Dresden class of light cruisers built for the Imperial German Navy (Kaiserliche Marine). Named for the town of Emden, she was laid down at the Kaiserliche Werft (Imperial Dockyard) in Danzig in 1906. Her hull was launched in May 1908, and completed in July 1909. She had one sister ship, Dresden. Like the preceding Königsberg-classcruisers, Emden was armed with ten 10.5 cm (4.1 in) guns and two torpedo tubes.
Emden spent the majority of her career overseas in the German East Asia Squadron, based in Tsingtao, in the Kiautschou Bay concession in China. In 1913, she came under the command of Karl von Müller, who would captain the ship during World War I. At the outbreak of hostilities, Emden captured a Russian steamer and converted her into the commerce raider Cormoran. Emden rejoined the East Asia Squadron, after which she was detached for independent raiding in the Indian Ocean. The cruiser spent nearly two months operating in the region, and captured nearly two dozen ships. On October 28, 1914, Emden launched a surprise attack on Penang; in the resulting Battle of Penang, she sank the Russian cruiser Zhemchug and the French destroyer Mousquet.
Müller then took Emden to raid the Cocos Islands, where he landed a contingent of sailors to destroy British facilities. There, Emden was attacked by the Australian cruiser HMAS Sydney. The more powerful Australian ship quickly inflicted serious damage and forced Müller to run his ship aground to prevent her from sinking. Out of a crew of 376, 133 were killed in the battle. Most of the survivors were taken prisoner; the landing party, led by Hellmuth von Mücke, commandeered an old schooner and eventually returned to Germany. Emden's wreck was quickly destroyed by wave action, and was broken up for scrap in the 1950s.