Short answers, pulled from the story.
Spanish explorers Antonio de Ulloa and Jorge Juan y Santacilia discovered platinum in 1735 in the rivers of Colombia. They observed Native Americans working the metal but initially failed to melt it themselves.
Karl von Sickingen developed a method to make platinum malleable in 1772 by alloying it with gold and dissolving the mixture in hot aqua regia. This process required precipitating the platinum with ammonium chloride and hammering the finely divided metal while white-hot.
Platinum has the atomic number 78. It is a silverish-white transition metal that does not corrode even at the highest temperatures.
The largest deposits are located in the Bushveld Igneous Complex in South Africa, which contains around 75% of the world's known platinum. Geologist Hans Merensky discovered the Merensky Reef within this complex in 1924.
The platinum-iridium alloy bar known as the international prototype meter was used to define the meter from 1889 to 1960. The previous bar made of platinum in 1799 had been replaced by this more durable alloy to ensure stability.
World production of platinum in 2010 was 170,000 tonnes. South Africa accounted for 77% of the total production that year.