Given the very early sites at which this ware occurs in the Spanish American colonies, this variety of green-glazed earthenware is probably of Spanish origin. Green-glazed coarse earthenware utilitarian pottery (such as the English Border Ware group) was produced in various centers throughout Europe, including Spain, in medieval and post-medieval times. This ware is distinguished from other green lead-glazed earthenware varieties in the FLMNH collection by the bright, clear green glaze color in combination with its light-colored paste.
This description of Green Lead Glazed Coarse Earthenware comes from the Historical Archaeology...
Cream to tan compact paste, usually with visible sand temper. Bright, clear green lead glaze, ranging from grass green to emerald green to a bright olive green. The glaze is smooth and reflective, usually occurring on both sides of the vessel.