Tin bent, a crackling sound known as the "tin cry" can be heard from the twinning of the crystals. Tin melts at low temperatures of about , the lowest in group 14. The melting point is further lowered to for 11 nm particles. β-tin (the metallic form, or white tin, BCT structure), which is stable at and above room temperature, is malleable. In contrast, α-tin (nonmetallic form, or gray tin), which is stable below , is brittle. α-tin has a diamond cubic crystal structure, similar to diamond, silicon or germanium. α-tin has no metallic properties at all because its atoms form
Wedding ring phrase of significance to the spouses. In many nations the engagement rings are plain while the bride's wedding ring commonly is bejeweled. Some customs include the wedding ring as the final of a series of gifts, which also may include the engagement ring, traditionally given as a betrothal present. This custom was practiced in ancient Rome and is possibly much older. In several traditions, the best man or maid of honour has the duty of keeping track of a couple's wedding rings and to produce them at the symbolic moment of the giving and receiving of the rings during the