Hi,

welcome on osm.
the value stone maze doesn't exist on osm, this value mix 2 different informations : a natural information (there are stones) and a geographic information (the stone create like a maze). This means we have to use 2 different tags.
For the tag natural, 2 values are possible: natural=stone and natural=rock, see  https://wiki.openstreetmap.org/wiki/Key:natural#Geology_related.
Which one is the best according to you ?

Best regards
Best regards