The rock looks like it will topple from a road-side viewing, and photos that a friend took from around the rock only makes the instability more apparent. (Although I can't recommend going on to the private property for a closer look at the rock).
This is only one of the many beautiful spots to take a rest at when travelling in the highlands.
Once you have sighted the cache container, please make sure there are no drive-by muggles before retrieving.
Thanks to TimeLibrarian for assistance in 'maintaining' / babysitting this from a closer distance.
For those who are into Waymarking you may be interested in visiting this on: Nature's Balanced Rocks