I believe at least 600

It doesn't go for 600 anymore. People usually sell them for 750-800 diamonds

I'm a pretty old player as in I haven't played in a while so yeah I see that too

WHAT??

last time i played they were 500

I think they went up when people started manipulating the prices of spikes, so now they're way higher.

I've seen this phenomenon happen on AJPW too with forests, it's may be due to the fact that diamonds/sapphires are easy to access and build up with while solids are very high demand (you can get nearly anything with them if you build them up, just like forests) causing there to be more buyers than sellers. Just my theory anyway lol, haven't played ajc in a while