Yes, indeed Dutch, town mark of Amsterdam, year letter X for 1806, the maker's mark
DLB in rectangle for
Diederik
Lodewijk
Bennewitz, registered in Amsterdam, 1785-1826. The lion of the province Holland, 1st standard mark, silver 934/1000. Crowned O duty free mark of 1807.
For Bennewitz see;
viewtopic.php?p=193670#p193670.
For the hallmarks see;
viewtopic.php?p=80323#p80323
Peter.
Source;
L.B. Gans, Premsela & Hamburger, goud-en zilvermerken van Voet. Karel A. Citroen, Amsterdamse Zilversmeden en hun merken.