Oh, I hope you're OK!
Have you heard of/watched the fruit of erm, I think it's called Oats Studio or something? The chap who directed District 9 and Elysium and Chappie has some short film setup going on.
Almost OK now thanks after arthritis flare-up in my right leg. Still limited in what I can do but getting there. I hadn't heard of Oats Studios but I have now and it looks like fun.
I thought it was pretty clear: a super-valuable mineral gem the size of a small hens egg they extracted from some kind of womb-like living plant or animal with a scalpel and acid. It was a kind of barter currency, so it formed the basis of a gold-rush economy with bandits, mercenaries and all.
It was pretty neat that the location was very earth-like (and obviously live-action filmed on earth, with almost no discernible cgi), but the environment felt very alien thanks to some very inventive and subtle touches.
It was a while ago, but I just wondered WHY it was so valuable. Would've been nice to know what it did. But not necessary of course. I suppose it would only have underlined the MacGuffin nature of it anyway.
I just figured it was some kind of futuristic diamonds, rubies or pearls and accepted it as such.