The name "topaz" is derived from the Greek Τοpáziοs, the ancient name of St. John's Island in the Red Sea which was difficult to find and from which a yellow stone (now believed to be chrysolite: yellowish olivine) was mined in ancient times.  Topaz itself (rather than topazios) wasn't really known about before the classical era. In the Middle Ages the name topaz was used to refer to any yellow gemstone, but now the name is only properly applied to the silicate described above.

Many modern English translations of the Bible, including the King James Version mention topaz in Exodus 28:17 in reference to a stone in the Hoshen: "And thou shalt set in it settings of stones, even four rows of stones: the first row shall be a sardius, a topaz, and a carbuncle: this shall be the first row." However, since these translations as topaz all derive from the Septuagint translation tòpazi[òs], which as mentioned above referred to a yellow stone that wasn't topaz, probably chrysolite, it should be borne in mind that topaz is not meant here.  The masoretic text (the Hebrew on which most modern bible translations of the Old Testament are based) has pitdah as the gem the stone is made from; pitdah is of unknown meaning, though scholars think it is related to an Assyrian word meaning flashed. There is a wide range of views among traditional sources about which tribe of the Israelites the stone refers to.

Yellow topaz is the traditional November birthstone (Blue Topaz for December), and the state gemstone for Utah.

Citrine, also called citrine quartz is variety of quartz.  It ranges in color from a pale yellow to brown. Citrine has ferric iron impurities, and is rarely found naturally. Most commercial citrine is in fact artificially heated amethyst or smoky quartz.  Brazil is the leading producer of naturally mined citrine, with much of its production coming from the state of Rio Grande do Sul.

Citrine gemstones are mounted on gold and silver and are used to make pendants, rings, charms, earrings necklaces, and other pieces of jewelry and it is often used as an alternate birthstone for the month of November.
Citrine has been used as jewelry for thousands of years and many believed that it has healing powers that can cleanse the body of toxins and other harmful elements and regenerate body tissue.
It is thought to generate positive energies such as confidence, optimism, and self discipline by those who wear citrine and also protects the wearer from depression, fear, and other maladies. 
Citrine is rarely found in a natural setting and most citrine gemstones are produced by heating other minerals such as amethyst and smoky quartz.
Deposits of natural citrine can be found in Spain, Namibia, Brazil, Myanmar, Argentina, the USSR, Scotland, and in the United States.