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 anniversary can receive a message from the monarch for 60th, 65th, and 70th wedding anniversaries, and any wedding anniversary after that. This is done by applying to Buckingham Palace in the United Kingdom, or to the Governor-General's office in the other Commonwealth realms. In Australia, where one can receive a letter of congratulations from the Governor-General on the 50th and all subsequent wedding anniversaries; the Prime Minister, the federal Opposition leader, local members of both state and federal parliaments, and state Governors may also send salutations for the same anniversaries. In Canada, one can also receive a message from the Governor-General