04-02. Topaz #1.
Topaz is the mineral of week #14 in this 52 weeks tour of Geometry of Nature. The topaz crystal belongs to the orthorhombic system – three unequal axes at right angles resulting in a rectangular prism with a rectangular base. It is very hard but easy to break. Pure topaz is colorless and transparent but, depending on the inclusions, it is often found in a wide range of color brown, blue, green, yellow, orange, red, pink, and purple.
The most important Topaz deposits are in Brazil. The famous golden orange-brown Imperial Topaz come from the famous occurrence in Minas Gerais at Ouero Prito. Multicolored yellow and blue Topaz comes from Russia. Classic yellow Topaz crystals come from Germany.
Legend has it that Hildegarde of Flanders, wife of Theodoric Count of Holland, presented a topaz to a monastery in the town of Ghent. It emitted a light so bright at night that prayers could be read without the aid of candles in the chapel where it was kept.