Topaz Inclusions: Part 2
Continuing from last week, examining some more Topaz inclusions. Specifically, multiphase fluid inclusions. What we see here is actually a combination of two types of fluid inclusions.
Firstly, the primary fluid inclusions, which formed simultaneously during the growth of the host Topaz. These are found on the prism faces parallel to the c-axis and are often multiphase inclusions that contain immiscible solutions and may also contain several daughter crystals.
The other type are the secondary fluid inclusions. These secondary fluid inclusions formed as a result of cleavage and fracture healing and are responsible for the formation of fingerprint inclusions in Topaz. These are usually found parallel to the basal pinacoid or on undulating fractures.
“Partially healed cleavages with bizarre two-phase fluid inclusions and usually lying parallel to the basal pinacoid do not only indicate a turbulent formation, but also hydrothermal crystallization. (Description under photos of Topaz from Pakistan).” PhotoAtlas Vol 2 – Pg. 731
Angular zoning can also be examined which becomes very prominent at certain angles.
Sheikh Fahad Abbas – GIA GG, AJP
Founder & Owner – Gemystique®
