I've seen vases in this shape ID'd as both Loetz and Kralik (although I suspect they may really be Harrach). You'll have to make your own conclusion, but whoever made this vase, it's a really super quality piece of glass. Great Art Deco shape, beautiful blue iridescence, and with silver mica inclusions.
Dimensions: 6" tall, 3" at it's widest point. Condition: Excellent Maker: Attributed Loetz Klostermühle Vintage: c. 1918