During the Early American pressed glass period (EAPG 1825 - 1910) homemakers, servants and/or slaves made their own butter from milk. It was a time consuming process and butter was considered a luxury food. Beautiful dishes were made to present the butter at the dining table. This rare table service butter dish is an excellent example.
Probably made by George Duncan & Sons / U.S. Glass circa 1880, pattern called Diamond Block, also known as Diamond Waffle, also known as Patricia. Other possible makers are Westmoreland Glass, pattern Gillinder, circa 1889; and Heisey made a limited pattern like this called ‘mitered diamond’. The shape of the knob points directly to Duncan and we are 90% sure it is by Duncan. (read more about Duncan glass)
Made of ‘White Glass’, a term used to describe flint glass. Flint glass is a very hard glass, and reflects a white sparkle. If broken, it separates into chunks. Usually made with quartz in the recipe.