The 1770 date is approximate for American manufacture of this type of ware in lead glass. Specifically Henry Stiegels second glassworks at Maniem, Pennsylvania.He brought competent glassmen from the continent including Bristol to compete directly with imported ware.
Incidentally, these were made well into the early 19th c. over here. An ad for the New England Glass Co, from 1825 shows a diamond molded example.