Six-ruble coin, 1837 Reverse side

Inside denticled rim, coin’s denomination
❀ 6 ❀ РУБЛЕЙ НА СЕРЕБРО (6 RUBLES IN SILVER); under decorative
line, year: 1837, and the mint mark: С.П.Б. (S.P.B.)
Circular legend: 4 ЗОЛ∙82 ДОЛ∙ЧИСТОЙ УРАЛЬСКОЙ ПЛАТИНЫ 💮
(4 ZOLOTNIKS AND 82 DOLYAS OF PURE URALIAN PLATINUM)
This coin was struck in polished collar dies. The edge bears the
owner’s mark—a horizontal rhombus with the initials ‘А Т’ inside.
The origin of the mark is unknown.