Ya I was going to mention this. I think it's cause Hive account@chamberpunk wanted to start with a simple example of a change in value without having to go into the complexities of what value actually is (because that's a huge fucking rabbit hole).

I thought this was a pretty succinct summary of marxist economics.

Value is baptismal = it has a non-existence and then an existence. It's produced by labor power, the commodity that has the peculiar quality of being able to produce more value than itself is worth.

All commodities gain value by labor imbued in them. Labor imbues them with:
a) use-value
b) exchange value

The Iron Ingot has use-value and exchange value. But it's inherent value quantity is determined by the socially necessary labor time required to produce the [Iron Ingot]