Val st lambert cut crystal vase

I have this signed Val st lambert crystal vase, green to clear in color with diamond cut I think. The color is in a swirl pattern and I am sure it's crystal and not glass because it is very heavy. Not sure if this is a modern peice or earlier. It has Val st lambert etched in the bottom of vase. I cannot find this price anywhere online and I am just trying to put a value on it and see when it dates from. I thought it was modern but could be mid century. Bought at auction a few years ago so that's all I know. Went to sell it to a guy who admitted he knew nothing about it and was offered 60 dollars, but I think it's worth more. Please help me find out how old it is and how much it may be worth. I can only see etching of name and no other marks.