Board Game Arena

Maybe the sign is a banana?

Can't stop is my guess!!!!!

The name of the game has not been found yet, which is not very surprising, since the second clue is: "very hard"
(just like this riddle, meh! )

Since carbon in very hard form is called a diamond, my guess would be Diamant by Bruno Faidutti and Alan Moon.

I would most like to see Carcassonne...

Power Boats? Maybe C means sea...

CATAN, I HOPE...

Sylla, maybe...

There is a new game called City of Iron

The good answer has been found on the french forum (it was easier as this is a recent game from a french publisher and it has not yet been published in english). But Anansi was very close: the answer is definitely about diamonds as the new game is Diam's from Lionel Borg, published by les XII singes. It's a combination card game in which you'll get rich collecting diamonds!