I am fairly sure it is of Swedish origin. The 3 crowns in the triangle are typical of a standard Swedish makers mark. The company that most probably produced it is Robert's Guldsmedja...."
Not sure about 1800s but Swedish hallmarks after 1912 include a triple crown mark, in a trefoil (three leaf clover) for local manufacture, and in an oval for imports..Swedish hallmarks after 1912 include a triple crown mark. Gold will bear a karat mark in a rectangle. There will also be a date letter and number, a city mark and a maker?s mark.
