Because of this, there exists the possibility of some smelters taking gold or silver coins and melting these down for the scrap value of the precious metals. A couple examples, in this regard, are worth mentioning here: US pennies have been made of copper-clad zinc since 1982, when they were before this time made of copper alloys; and British pennies were once made of 97% copper, but are now made of copper-plated steel. Throughout history, gold has served as a measure of value and a symbol of wealth. It is one of the coinage metals (along with silver and copper). It is used, customarily and legally, as a means of payment or a medium of exchange. Gram and troy weight are the units of measurement used for gold. To indicate the amount of gold present in, say, a piece of jewelry, the term "carat" is used. Because it was first chanced upon in silver mine in South America, platinum was named as such, after the Spanish word "platina", which translates to "little silver". 2. Palladium - William Hyde Wollaston, an English chemist and physicist, discovered palladium in 1803 in samples of platinum ore obtained from South America. Two examples are given here: One is the 100,000-euro Vienna Philharmonic, minted in 2004, which contains 31 kilograms of gold; the other is the 1 million-dollar Canadian Maple Leaf, minted in 2007, which contains 100 kilograms of gold. Three factors - metal, purity, and weight - affect the value of bullion. Because of its naturally white properties, palladium has been used as an alternative to white gold. Along with silver and nickel, palladium is popularly used in making white gold alloys. According to the British Geological Survey (BGS), the top four palladium-producing countries in the world are Russia, South Africa, Canada, and the United States (in this order). The expenses incurred in relation to the handling of the fund are charged through the selling of a certain amount of the gold as represented by the certificate. Over time, the amount of gold in the certificate, as may be expected, decreases. Entering in a Contract For Difference (CFD): Some of the noted financial services firms, especially those in the United Kingdom, provide Contract for Difference (CFD).