Handmade cobalt and white glass vases

I found these two beautiful vases a year ago and fell in love with them on sight! They are both cobalt and white glass. The tall one measures aprox 15 in and the smaller one about 7.5 in. The bottom of the vases are shaped like a tree trunk and the tops are like a flower. Both vases start as cobalt on the bottom and flow to white, while the inside is all cobalt. I have never seen anything like them and curious as to who made them and where they come from.