Hm..
its good to read that Optical feels the needs we have in game.
I wouldnt reduce more the Coal, but I would reduce Lapiz to 6-7k and diamond to 50k. I dotn care about mathematical progress to the numbers, just to create some difference.
On the other hand, if you compare it with the prices that exist, with the 98,000 of diamond you can buy over 40 coal. Why dont you do it guys, and just to place the stones around your buildind, so to cover the whole place? Why do you need just one?
Its not logical. Does the Diamond ore offers benefits? Makes you feel/be/seen are rich in the game?
Damn no. Now that I am thinking, NO!. Coal to 2k, Lapiz to 6-7 Diamond as it was!