Cobalt green, also known as Rinman's green, is a pigment with a rich history and distinctive properties. It is a compound of cobalt(II) oxide and zinc oxide. The pigment is known for its excellent lightfastness and heat stability.

Cobalt green has been used in art and ceramics for centuries, with its use dating back to ancient civilizations. It gained popularity in the 19th century as a replacement for the toxic copper-based greens such as verdigris, due to its improved stability and safety. The pigment's unique green color, combined with its durability, made it a favored choice for artists and artisans seeking a reliable and beautiful green hue for their works.