Quartz Countertop Unsupported Span. They are built to be rigid, so, there may not need to be any support between the spans since you are supporting it on the sides and the back. This granite top is doomed for failure the moment someone decides to sit on it, unless a support is put underneath it.
For the other materials (Corian, Cambria Quartz, etc) the considerations are many and too detailed to discuss here. Your stone countertops appear to float with countertop support brackets from Original Granite Brackets. There's laminate, granite, marble, soapstone, quartz, stainless.
I wonder if anyone else has had this problem.
This is an appropriate thing to consider since there are many people choosing to go with quartz for their countertop surfaces.
Also, avoid scraping sticky messes off. Your stone countertops appear to float with countertop support brackets from Original Granite Brackets. For the other materials (Corian, Cambria Quartz, etc) the considerations are many and too detailed to discuss here.