Plant looks like a white-flowered A. carnea but I grew it as Androsace darvasica. First flowers just starting to open.
Very nice! Looks like you'll have some brilliant colours to look forward to as the flowers are feritlized:http://www.androsaceworld.com/fotogallerij/darvasica/index.htm
Calgary, Alberta, Canada - Zone 3
-30 C to +30 C (rarely!); elevation ~1130m; annual precipitation ~40 cm