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.
First they changed the so-called Polka rhythm to the Habanere rhythm and secondly they called it Tango. In 1907 the dance was introduced in France; by 1912 it crossed the channel to England. The dance was so popular in France and England that Tango teas became the rage. It was danced in the United States first by the Castles who elevated it to a dance accepted in any ballroom, by purifying it of its coarse associations and turning it into a thing of beauty.