Olivine has the formulae (Mg,Fe)2SiO4 and a relative hardness of 7. It's name is derived from the characteristic olive green colour. A common rock forming mineral. A clear green variety is called peridot and has some uses as a gem.
Hear it on YouTube. Here's a piece that many people know, and rightfully so! This famous classical piece from the romantic period is one of those pieces that has the ability to make anyone feel happy. Composed in the 1920s, for a ballet, the piece was an instant success.
Originally for four couples in square formation, it was a courtly version of an English country dance, the forerunner of the quadrille and, in the United States, the square dance. It was for some fifty years regarded as an ideal finale to a ball but was eclipsed in the early 19th century by the quadrille.otillion figures demonstrated in the Festsaal, Hofburg, Vienna, in 2008. For other uses, see Cotillion (disambiguation) . The cotillion (also cotillon or French country dance) is a social dance, popular in 18th-century Europe and America.