Covered Beaker with Raised Square Pyramids and Incised Oval Design

This beaker was probably intended to imitate earlier 17th-century glass works, which used gold to make a luminous red. The red color of this work was achieved with copper instead of gold. Copper-red glass is so dark that it appears almost black. To achieve transparency, copper-red glass is sometimes ground into a fine powder and then mixed with hot, molten clear glass.