Mimesis is 9,75€
1765 Steam Gems is about 1€ of selling value
Why anyone would (and how) do that?
1000 gems (1 sack that is sellable) is circa 0.45€ without Steam fees.
If it's 1765 × €0.01 = €17.65 why you would give €17.65 for a 9.75€ game?
Also 20 Refined Metals is about 0.5€
So your items are slightly over 1€.
You can have individual gems but why, they are useless. You can sell (on Steam market) only sack of gems which is 1000 gems. 1 gem doesn't cost 0.01€ because individual gems are not sellable.
You can't buy gift into your inventory, someone can gift it to you only directly so you need to activate it. Or you can buy it yourself to your library. Yes you can also buy key for this game but isn't much cheaper than on Steam store.
To buy game on Steam you will need to have (and sell) almost 22 sack of gems so almost 22000 gems, not 1765 gems :D if you want to buy it this way. Easier will be if you simply but the game directly for your real money.