Investing in gold is a way of protecting against crises that may be brought about by economic or political instability or by social unrest. There are at least six ways of investing in gold: Buying gold coins: This is the most popular way of investing in gold. Gold bullion coins are typically priced based on their weight; a premium is added to the gold spot price. However, ionic chemical compounds of gold (example, gold chloride) can be extremely harmful to the kidneys and liver. Platinum: Findings by the U.S. federal agency CDC reveal that exposure to platinum salts, on the short term, may cause nose, throat, and eye irritation. Long-term exposure to these compounds, on the other hand, may cause skin and respiratory allergies. Mexican Centenario, Libertad, and Onza 6. Polish Orzel bielik 7. South African Krugerrand 8. Swiss Vreneli 9. British Britannia and Sovereign 10. American Buffalo, American Eagle, and Double Eagle The 10,000-dollar Australian Gold Nugget is one of the world's largest bullion coins. Minted by the Australian government, this bullion coin is made of 1 kilogram of 99.9% pure gold. The Perth Mint Certificate Programme, which is fully guaranteed by the Government of Western Australia, is the only silver certificate program in the world that is guaranteed by a national government. Trading in Exchange-Traded Funds (ETFs): An investor can have an easy way of gaining exposure to the price of silver through an ETF. Thus, metals that are labeled "precious" are also considered noble metals (note, however, that noble metals are not necessarily precious metals). There are nine known precious metals - gold, platinum, iridium, palladium, osmium, silver, rhodium, ruthenium, and rhenium. With the exception of the latter, all are considered noble metals. Because it's wear-resistant and does not tarnish, platinum is highly valued by jewelers, especially watchmakers. In 2008, its price went up to as high as 2,252 U.S. dollars per troy ounce. Being rare and, therefore, very precious, platinum has been made synonymous to things that are considered "of the highest quality".