Pretty Glass Vase with a Mark, Need to ID Mark

I bought this vase as part of a box lot and assumed it was Mikasa because everything else in the box was. But there's a mark on the bottom I've never seen before and now I'm curious what it could be. The vase is 8" high. It has a triple repeating pattern like grass fronds that come out of the base. The mark was extremely difficult to photo, did my best, hope you can see it ok. TY!

 

The big miters (the groves are called miters) were pressed when the glass was made (in the mold). The small gray groves were cut subsequent to that. An additional bit of decoration.

 

So technically, can be called cut crystal. I don't know the mark, but likely someone here will.

 

I was intending to place this in my space at the antique mall because it's pretty. I sell a lot of vases there. Then I saw the mark, have never seen it before and was curious. Who knew it would become a bit of a brain buster?! To me, it looks like a C with a cane. It's likely newer, maybe 80s or later.