How stable are your formulations?

I once made a shampoo formula that I kept for about 17 years.  It was my first batch of anything and for some reason I just never disposed of it.  It stayed stable for about 7 years before it striated into three layers.  I suspect if it were a clear shampoo that would not have happened. 

Anyway, 17 years seems pretty impressive but not nearly as impressive as this cream which is just about 2000 years old.  The formula contained animal fat, starch and tin dioxide.  Even more interesting, the scientists who analyzed it made a copy of the formula.

Perhaps the 2000 year old sample wasn't completely stable (no one said whether they tried it or not) but it doesn't look separated in the picture.  That's an impressive feat by an ancient cosmetic chemist.