Topaz is a gemstone available in a rich rainbow of colours. Prized for several thousand years in antiquity, all yellow gems in antiquity were called topaz. Often confused with citrine quartz (yellow) and smoky quartz (brown), quartz and topaz are separate and unrelated mineral species. The most prized colour of topaz is called Imperial topaz after the Russian Czars of the 1800s and features a magnificent orange body colour with pinkish undertones. Topaz also comes in yellow, pink, purple, orange, and the many popular blue tones.
Citrine, the other birthstone for November is known as the “healing quartz”. This golden gemstone is said to support vitality and health while encouraging and guiding hope, energy and warmth within the wearer. Citrine can be found in a variety of shades ranging from pastel yellow to dark brownish orange. It is one of the most affordable of gemstones and plentiful in nature. Citrine is found most frequently in Brazil, Bolivia, and Spain.
Information from http://www.americangemsociety.org