Figures of the Article

• A pair of turquoise and lapis lazuli earrings (a) and the hue range of "Qing" color (b). The 12-color circle is defined with HSB (H-hue, S-saturation, B-brightness) color model. The H values are in degrees (°) and increase every 30° in clockwise direction from 0°, S=B= 100%. The grey-colored arc is from 87°to 239°
• "Blue" and "Qing" (blue-green) in nature, Mount Fitzroy, Patagonia
• Turquoise artifacts from Jiahu site about 8 000-9 000 years ago (a, b) and a turquoise dragon from Erlitou site (1740-1600 BC)(c, d), both in Henan Province, China
• Tutankhamun pectoral, the 18th Dynasty of ancient Egypt(Egyptian Museum, Cairo)(a)and pectoral and necklace of Sithathoryunet with the name of Senwosret II, the 12th Dynasty of ancient Egypt(Metropolitan Museum of Art)(b)
• Ram in the thicket (a)and lyre fragment bull head (b) from the Royal Cemetery at Ur(University of Pennsylvania Museum of Archaeology and Anthropology)
• The main ancient mines of turquoise and lapis lazuli, and the general flow direction of lapis lazuli in Eurasia
• Dark green glaze ring with grain patterns from the Warring States Period (Yiyang Municipal Museum, Hunan Province, China)
• Foliated dish with floral scrolls, early Ming Dynasty(Metropolitan Museum of Art)(a); turquoise blue porcelain vase embossed with dragon, phoenix, and peony pattern, Qianlong, Qing Dynasty(Palace Museum, Beijing)(b); and lapis lazuli blue double handle porcelain pot with gold color cattle, Hongzhi of Ming Dynasty(Palace Museum, Beijing)(c)
• Turquoise faience scarab from the temple of Hatshepsut, the 18th Dynasty of ancient Egypt(Metropolitan Museum of Art)(a); pectoral with glaze of lapis lazuli blue, the 19th Dynasty of Ancient Egypt(British Museum) (b)
• Faience winged Goddess, the 19th to 22nd Dynasty of ancient Egypt (Metropolitan Museum of Art) (a); and eye of Horus ring made of faience (b), the 18th Dynasty of Ancient Egypt (Museum of Fine Arts, Boston)
• Annular blue Mesopotamian glass beads (National Museum of Denmark)
• Brick reliefs of walking lions from ancient Babylon (a) and the entrance of Shah mosque of Isfahan (b)