Crystal structure "white tin" respectively. Two more allotropes, γ and σ, exist at temperatures above 161 °C and pressures above several GPa. White tin is metallic, and is the stable crystalline form at or above room temperature. Below 13.2 °C, tin exists in the gray form, which has a diamond cubic crystal structure, similar to diamond, silicon or germanium. Gray tin has no metallic properties at all, is a dull gray powdery material, and has few uses, other than a few specialized semiconductor applications. Although the α–β transformation temperature of tin is nominally 13.2 °C, impurities (e.g. Al, Zn, etc.) lower the
Diplomatic gift A 2012 gift of a "British" table tennis table to President Obama seemed ideal until it was revealed that it was designed in Britain but made in China, evoking worries about the decline of British manufacturing industry. Diplomatic gifts take diverse forms: Diplomatic gift A diplomatic gift is a gift given by a diplomat, politician or leader when visiting a foreign country. Usually the gift is reciprocated by the host. The use of diplomatic gifts dates back to the ancient world and givers have competed to outdo each other in the lavishness of their gifts. Examples include silks given to