Joan Clarke, woman who cracked Enigma cyphers with Alan Turing. Read more about sharing. Joan Clarke's ingenious work as a codebreaker during WW2 saved countless lives, and her talents were formidable enough to command the respect of some of the greatest minds of the 20th Century, despite the sexism of the time.
A semitone, also called a half step or a half tone, is the smallest musical interval commonly used in Western tonal music, and it is considered the most dissonant when sounded harmonically. It is defined as the interval between two adjacent notes in a 12-tone scale (e.g. from C to C â¯).9-tone equal temperament distinguishes between the chromatic and diatonic semitones; in this tuning, the chromatic semitone is one step of the scale (play 63.2 cents (helpÂ·info)), and the diatonic semitone is two (play 126.3 cents (helpÂ·info)).
Any gemstones that is not a diamond, ruby, emerald or sapphire is a semi-precious gemstone. Calling a gemstone semi-precious does not mean it is less valuable than precious gemstones. Semi-precious gemstones are just usually more abundant (but there are a few exceptions).The value given to semi-precious gemstones depend largely on color, availably and quality. Many of these gemstones are a deep yellow, but can be light or dark yellow, a golden orange and a brown orange. 2  Citrine is a transparent quartz that gets its yellow color from iron. 3  It usually has excellent clarity and few inclusions.