The vivid blue of the mineral pigment ultramarine (群青, gunjō), or a similarly vivid blue. The raw material for ultramarine is lapis lazuli — a precious mineral since antiquity, making paintings using ultramarine appear noble. Because it consists of crushed blue mineral particles, the name "群青" means "a gathering of blue." Since the 19th century, similar colors have been artificially synthesized without lapis lazuli. When speaking of ultramarine skies or ultramarine seas, the image conveyed is one of pristine clarity.