SPARKLING  CONGAC TOPAZ

This is a  well facated  natural  clean topaz stone which has been  heat treated to enhance the colour.

Mined in Brazil

ROUND

Grade A colour

Transulant

Grading VVS

Total weight  10.60 cts app

Size 13 x 8  mm

Topaz is commonly associated with silicic igneous rocks of the granite and rhyolite type. It typically crystallizes in granitic pegmatites or in vapor cavities in rhyolite lava flows.

Pure topaz is colorless and transparent but is usually tinted by impurities; typical topaz is wine, straw yellow, pale gray or reddish-orange. It can also be made white, pale green, blue, gold, pink (rare), reddish-yellow or opaque to transparent/translucent.

Topaz has a hardness of 8 on the Mohs scale and is the hardest silicate along with beryl (Aquamarine). The Toughness of Topaz is Fair. Topaz crystallizes in the orthorhombic crystal system, with an "Elongate Prismatic" crystal habit. Pinacoid, multiple domes and orthorhombic pyramid faces produce complex and multifaceted terminations that are well formed. Topaz has a chain-like lattice structure of irregular octahedrons. Topaz has perfect (easy) basal cleavage in one direction (in the plane perpendicular to the c-axis), with a conchoidal fracture, therefor it is a difficult stone to set without fracturing. Topaz has a refractive index of 1.610 to 1.630.