Tin pest related problems such as tin whiskers. At 13.2 °C (about 56 °F) and below, pure tin transforms from the silvery, ductile metallic allotrope of β-form "white tin" to the brittle, nonmetallic, α-form "grey tin" with a diamond cubic structure. The transformation is slow to initiate due to a high activation energy but the presence of germanium (or crystal structures of similar form and size) or very low temperatures of roughly −30 °C aids the initiation. There is also a large volume increase of about 27% associated with the phase change to the nonmetallic low temperature allotrope. This frequently makes tin
Wedding ring Wedding ring A wedding ring or wedding band is a finger ring that indicates that its wearer is married. It is usually forged from metal, and traditionally is forged of gold or another precious metal. The earliest examples of wedding rings are from Ancient Egypt. Western customs for wedding rings can be traced to ancient Rome and Greece, and were transmitted to the present through Christendom in Europe, which adapted the ancient customs. Depending on culture, a wedding ring is typically worn on the base of the left or right ring finger, if the wearer is left handed often it