If you want to invest in physical metal get tungsten welding rods. It is in standard quantifiable sizes (e.g. 3.2mmx175mm rods are just under an ounce and all weigh the same) and readily available. Rods are typically about $4 per unit and are in a commercially usable form, which makes up for its non-precious status versus bullion/coins regarding trade. As they are basically all made in China the labour premium is low. Currently the price is about $100/kg: Compare to base Nickel ~$10 and silver ~$700. Combined with relative rarity (rarer than silver), its unique industrial properties (hardest, highest melting metal) and applications (e.g. component of tool steel, drill/grinder bits as carbide) it is basically a no lose proposition. On account of its density and hardness it can't be counterfeited with cheaper material. As each unit is worth a much smaller amount it can be easily used in trade for everyday items if you're into alternative non-fiat currency. You can fit about $1500 worth in a 1L container, so storage space isn't much different to encased silver coins. And of course if you weld you can actually do something useful with them. All in all, its actually quite a smart investment particularly if you only have a small amount of cash to spare.
