Why is urnas blue?

Urnas, or urns, can appear blue due to various factors, including the materials used in their production, such as pigments or glazes that impart a blue hue. In some cultures, blue is a color associated with specific meanings, such as tranquility or spirituality, which may influence the choice of color. Additionally, certain historical pottery techniques, like those used in ancient China or the Mediterranean, often featured blue as a prominent color due to the availability of cobalt and other blue pigments.