SPC (Stone Composite Flooring) ??

SPC is a bit of "proprietary" term used by a Chinese manufacturer of rigid core LVT. The WPC (Water Proof Core)/Rigid core product is a variant of LVT that is meant to combine the best aspects of laminate flooring (rigidity and durability) with the best aspects of LVT (Appearance, clean-ability, topical moisture resistance).

The WPC / Rigid core format of LVT has been on the market now for about 3 years. It's proving to be extremely durable and less problematic to the floating versions of LVT.

The SPC is a twist on the composite vinyl core that many manufacturers are using in that it incorporates limestone dust into the mix. This isn't really anything new to the industry as limestone dust has been used for decades in the manufacture VCT (Vinyl Composition Tile) - the 12" x 12" waxed tile you see in most surpermarkets, walmarts, targets, etc. It's a stable and cheap filler that binds well with vinyl. It's a way to make their product stand out from a crowded field of other good products. In my opinion more of a marketing thing than a huge benefit in performance.