Anyways, the only way this works is because gold has a static market supply, which it does due to rarity. BUT, that STILL doesn't answer the question of WHY. I still don't get it. Maybe it's one of those things where it has to be something, so why not this.
The major reason it has value today beyond it's usefulness is because it historically has had value due to its usefulness. Now it's a self-sufficient, or tautalogical, system - gold is valuable simply because gold is valuable.
In early human history gold could be found with very little effort. In some areas you didn't even mine it, you simply looked for the shiny rocks. Because it existed in the environment in its ideal human-use form, it was valued. The fact that it could be easily worked, didn't kill people for using it (ie, lead), and was naturally more scarce than, say, dirt, it was valued first as a commodity.
People used it as jewelry due to the combination of ease of work, and due to the fact that using an important item as jewelry suggests to others that you have enough to meet your basic needs, and you can "afford" to waste some as decoration. Until you actually work gold with your own hands and then attempt to work
any other metal, you really have no idea just how huge a deal this is. It's not just "easy to work" it's like butter - you can make any shape out of it. In fact this is why we almost always use it in alloys such a 14k - pure gold would bend and scratch a lot more easily than the alloys.
It's a
pleasure to form gold. It can be pulled into seemingly impoosibly thin wires without breaking. It can be beaten to one atom's thickness mechanically. It melts and softens as low temperatures compared to other metals. It's not a minor attribute.
In early barter systems gold was bartered just as food and other commodities were. However, due to it's usefulness and relative
global scarcity, people figured out that if they needed an item from a distant place, taking a cow, or three bags of grain with them was more trouble than taking a small sack of gold.
It became a de facto currency due to ease of transport, and universal usefulness and appeal, which was preceded by its scarcity. If everyone had as much gold as they had water, and it rained gold seasonally, then you wouldn't trade your grain for it - you have as much as you need. However, one could, at that time, always find a practical use for the metal.
Scarcity plays a very significant role in how much something is valued for bartering.
So:
Gold is valuable today because we agree that it's valuable (ie, social contract).
We agreed on its value due to
- Relative global scarcity (there were societies that treated it as trash merely because they had so much of it, despite its usefulness)
- High natural usefulness (doesn't tarnish, easy to work, easy to find early on, low melting point, easy to purify, not poisonous, brilliantly shines in the human visual spectrum, etc, etc, etc)
- Ease of transport
The above three points made it an ideal tool for bartering, and so we formed this social contract to agree, as humanity, to value it.
Gold is an oddity in this regard - it now has a lot more social value than practical value. Thus it is much more likely to experience fluctuation due to human perception more than to supply or demand, which is why normal economic models don't apply.
Added at: 12:24
Keep in mind, though, that even though it has a high social value, the fact that we still use it industrially at it's insane cost indicates that there really is
no other replacement. Its extraordinary properties are
well worth the cost for many things, which only reinforces the belief that gold is valuable.
If it were not for its continued usefulness in industry, it would very likely bubble and deflate.