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
Wedding ring Romania, spouses celebrate their silver wedding anniversary, i. e., twenty-fifth anniversary, by exchanging silver wedding rings, which are worn on the fourth finger of the left hands along with their original, and usually gold, wedding rings. While most Christian Churches (such as the Catholic, Lutheran, and Anglican) have the exchange of rings within their wedding liturgies, some Christian denominations eschew the use of wedding rings. The wearing of plain dress has historically been practiced by many Methodist Churches, in keeping with the teaching of John Wesley, who stated that people should not be "adorned with gold, or pearls, or costly