Some people hate carrying around coins and just save them up in jars or throw them into water fountains. There is a never-ending discussion over whether or not to stop printing the US penny, but some folks just don't like rounding to the nearest nickel. Some new coins have been extremely popular (eg. the US state quarters), and all sorts of organizations are starting to print new kinds of collectible coins. Here are just a few examples of some not-so-rare coins.

• Military "challenge coins" are generally bestowed upon members of the armed forces for exemplary service and to boost morale. But other areas of the government have printed coins, too -- such as the secretaries of education, transportation and agriculture, as well as the Department of Agriculture's Office of Information Technology. If this coin tradition spreads, will there be inflation? [url]
• The US mint has previously produced half-cent, two-cent, three-cent and 20-cent coins -- so why not an 18-cent coin or a 32-cent coin? The argument is that these additional coins would minimize coin transactions, but how about a 99-cent coin? [url]
• The world's smallest coin could be a speck of diamond (about 750 nanometers across) with Elizabeth Windsor's profile etched on it. Nano-etching the lab-grown diamond demonstrates the capabilities of the James Watt Nanofabrication Centre at the University of Glasgow -- and similar processes could be used to produce patterns for novel semiconductors and nano-transistors. [url]

If you'd like to read more awesome and interesting stuff, check out this unrelated (but not entirely random!) Techdirt post.

There are plenty of good reasons why gold is a valuable element that has been used as money instead of other substances in nature. Diamonds might have been an interesting form of carbon to use in a monetary system, but diamonds don't actually last forever. Here are just a few quick links on diamonds.

• Candle flames can create diamond particles very briefly, but the diamonds are burned away in the process. About 1.5 million diamond nanoparticles are created every second as a candle burns, actually. [url]
• Diamond is thermodynamically unstable, but it was only recently discovered that it can actually lose mass slowly under UV light. Physicists found this out when they couldn't make a diamond-based UV laser that lasted for more than 10 minutes... [url]
• Diamonds have a high index of refraction that makes them sparkle. But there are possibly other forms of carbon that could be more sparkly -- if only they could be synthesized. [url]
• To discover more interesting science-related stuff, check out what's currently floating around the StumbleUpon universe. [url]  

By the way, StumbleUpon can recommend some good Techdirt articles, too.