#gemystique
Calcite, Iceland Spar is not a gem that comes to mind when one talks about fine gemstones. Due to its 3 cleavage directions and its low hardness (Mohs 3) it is not durable for everyday wear. But from a gemological standpoint, they can be fun to examine. With a significant birefringence of 0.172, they display strong eye visible doubling. When you inspect it in the microscope next time, make sure to use a polarizing filter and enjoy the aftermath.
Calcite can have fingerprints, which range in appearance from very minute swirly ones to the typical standard FP’s
The varying lighting conditions make the internal cleavage planes pop out and they can be very beautiful to observe. Calcite is probably the best gem for new students to learn about the concept of cleavage in gems and how it effects durability.
Sheikh Fahad Abbas – GIA GG, AJP
Founder & Owner – Gemystique®
