Bayer Salz Seal, Image by StuE, Found by Irish Mikek
Found in Augsburg, Bavaria, South Germany, 20mm(max), 6.2g.
A large part of the markings on this seal are missing.
Remainder looks to be the Lesser coat of arms of Bavaria on one side. The number of lozenges looks to be closer to the 21 used from the 15th century rather than the 42 when Bavaria became a kingdom in 1806. See here.
The other side has a circular rope-cable border with .S. inside at the top beneath which are fragments of two other letters (MT?)