Zircon (rare gem crystal)
Thumbnail, 1.9 x 1.1 x 1.0 cm
Harts Range, Central Desert Region, Northern Territory, Australia
Ex. Kay Robertson

Very fine, totally gemmy single crystal of Zircon from the Harts Range in Australia. This single, pyramidal crystal is completely gemmy, and it has an attractive, water-clear, light amber color. The crystal is actually doubly-terminated, with some contacting only on one face of one termination. It is a competitive-level, display quality thumbnail of a very common species, in very rare quality and clarity. Considering that the only other Zircon in Mindat for this area is opaque, this 8.67 g crystal is rather remarkable. It is even better in person. Kay has owned this since 1975. As well, zircons have a profound scientific importance as reservoirs of the earth's history and a way to date the rock they are found in. Per WIKIPEDIA: Zircon has played an important role during the evolution of radiometric dating. Zircons contain trace amounts of uranium and thorium (from 10 ppm up to 1 wt%) and can be dated using several modern analytical techniques. Because zircons can survive geologic processes like erosion, transport, even high-grade metamorphism, they contain a rich and varied record of geological processes. Currently, zircons are typically dated by uranium-lead (U-Pb), fission-track, cathodoluminescence, and U+Th/He techniques. For instance, imaging the cathodoluminescence emission from fast electrons can be used as a prescreening tool for high-resolution secondary-ion-mass spectrometry (SIMS) to image the zonation pattern and identify regions of interest for isotope analysis. This is done using an integrated cathodoluminescence and scanning electron microscope.[19] Zircons in sedimentary rock can identify the sediment source. Great zircons, truly great ones, are both scientifically important and important to the collector as well.