Topaz,   Al2[SiO4](OH,F)2, which is colorless in its pure mineral.

It may become a beautiful crystal with impurities from other elements.  So what is it that constitutes the difference between the real topaz and the citrine? A fluorine aluminium silicate in chemical terms, the topaz is considerably harder and heavier than quartz, and it has a higher refractive index, which endows it with more fire "when" the colour is good. Its hard to find.

It does have one weakness: its good cleavage qualities, which must be taken into account when it is being worked on. It can be found in all the colours of the rainbow and has been known to Man for at least 2000 years. It has not been proved beyond doubt whether the name comes from Sanskrit or Greek, though the Greek name 'topazos' means 'green gemstone'. The Romans dedicated the topaz to Jupiter.

The topaz has been known for much longer than 4000 years and is one of the gemstones which form the foundations of the twelve gates to the Holy City of the New Jerusalem when it comes down after World War 3 kills billions.

Revelation 21:19 "And the foundations of the wall of the city were garnished with all manner of precious stones. The first foundation was jasper; the second, sapphire; the third, a chalcedony; the fourth, an emerald;
  20 The fifth, sardonyx; the sixth, sardius; the seventh, chrysolite; the eighth, beryl; the ninth, a topaz; the tenth, a chrysoprasus; the eleventh, a jacinth; the twelfth, an amethyst.
  **21 And the twelve gates were twelve pearls; every several gate was of one pearl: and the street of the city was pure gold, as it were transparent glass.
  22 And I saw no temple therein: for the Lord God Almighty and the Lamb are the Temple of it."**

	Mine Rough Peach Topaz 200 Carats Afghanistan - 7	Not For Sale
	Stunning Hot Pink Natural Topaz 17.40 Carats From Brazil 7 Minas Grais Appraisal from England:	$8500
	Sparkling AAA London Blue Topaz Cushion Cut 16.55 Carats 14.6x15x8.6 mm From Brazil 7	$1600