So, I did it. It's kind of ironic, after doing all my calculations for the perfect land plot and such based on stone - it has become almost worthless. It's impressive how quick the decline was from being the most lucrative resource to mine to being a money loser.
Stone is at a grain factor of 0.47 now. That means, for each PP you have on Stone, you only get 0.47x of what you would get for Grain. Since you have to pay 0.5 Grain for each PP to feed the workers, you're now losing 0.03 on each Stone produced - without bonuses.
Let me walk you through this.
I have a rare stone plot in Viritas. It currently looks like this:
2,445 Stone ready to harvest, at a cost of 11,228 Grain.
I have two boosters on the plot - 10% for being rare, 10% for card type.
And yet, even here, with 20% bonus, I'm losing money:
With 20% Bonus. Impressive, isn't it?
I blame the Castles & Keeps, obviously, for taking their 10%. Death to the Bourgeoise! Instead of blaming the market. It's a normal mechanism. We have it here in real life basically every year. There's an under-production of potatoes, so the price for potatoes goes up and farmers who sew potatoes made a lot of money. All the other farmers see that, so they plant potatoes, too. Next year, everyone has too many potatoes, and the price goes slumps quicker than Bitcoin these days. Meanwhile, those who stuck to carrots or onions are making a fortune because they didn't switch and now there's an underproduction of carrots and onions - because so many switched from those to potatoes.
I guess you get it. There was an underproduction of stone, so everyone (including me) focused on stone - the production went up heavily.
It's going down now for the same reason. Maybe Stone will be the next carrots? No.
Why not?
Because the cards used for Stone production are mostly the same used for Iron production, and Iron, well, it's not in a good space either with a Grain Factor of 0.55, barely profitable after taking out the 10% tax and 10% conversion. You can actually see that with the decline of Stone production due to losses, Iron production went up:
Terrains for Stone: Desert, Canyon, Hills
Terrains for Iron: Mountains, Badlands, Caldera
Cards for Stone: Fire, Death, Dragon, Life
Cards for Iron: Fire, Death, Dragon
Fire, Death, Dragon. Life can be used in several other terrains, so no worries about that.
Fire? Nowhere else.
Death? Bog (Grain) and Swamp (Wood)
Dragon? Only Plains (Grain)
But one has to have the right plots to be able to swap the cards. And Fire cards? Well, there's always the option to put them on Wood or Grain without the 10% bonus. Better than nothing.
Or buy Totems and wait for the winds to change.
I halted my Stone production and will allocate the cards to other fields. Greener fields. Maybe even buy a Plain for the many Dragon cards I have - but then again, given my luck, everyone will do the same and before I know it, I planted potatoes with everyone else when I should've stuck with carrots.
Disclaimer: 5% of this post go to 
Former posts:
Calculating Land part 1 - How to get your ROI
Calculating Land part 2 - Are pools worth it?
Calculating Land part 3 - Organic Growth
Land Plot Efficiency for non-whales
Card-Production-Coefficient - Combining LPE and ROI
Renting for Land - at what cost?
Risks to my strategy
What do refined resources cost?
Real cost of Wagons
Calculating Totem and Title boosts
Calculating Plot Rarity Boost
Setting up a Rare Stone Plot
My perfect plot - Conclusion of my calculations
Thank you very much for reading, I hope you enjoyed it at least as much as I enjoyed writing :-D If you have any comments or feedback - please let me know! And don't forget to leave your own posts for me to curate. Thank you very much!
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