Emerald says: "§ 23.23(c) It is unfair or deceptive to use the word "laboratory-grown", "laboratory-created", "[manufacturer name]-created", or "synthetic" with the name of any natural stone to describe any industry product unless such industry product has essentially the same optical, physical, and chemical properties as the stone named." Emerald is regarded as the traditional birthstone for May as well as the traditional gemstone for the astrological signs of Cancer. One of the quainter anecdotes about emeralds was told by the 16th-century historian Brantôme, who referred to the many impressive emeralds the Spanish under Cortez had brought back to Europe from Latin
Western Mexico shaft tomb tradition was not a unified cultural area. Archaeologists, however, still struggle with identifying and naming the ancient western Mexico cultures of this period. The shaft tomb tradition is thought to have developed around 300 BCE. Some shaft tombs predate the tradition by more than 1000 years – for example, the shaft tomb at El Opeño in Michoacán has been dated to 1500 BCE but is linked to Central, rather than Western, Mexico. Like much else concerning the tradition, its origins are not well understood, although the valleys around Tequila, Jalisco, which include the archaeological sites of Huitzilapa and Teuchitlan, constitute its