Mobile Fluorite in Quartz
In 2005, a deposit in Madagascar yielded quartz that showed beautiful blue to purple octahedral fluorite crystal inclusions (Summer 2005 GNI, pp. 180–181). This author recently examined a unique example of this material in which a fluorite crystal was much smaller than the cavity it occupied (figure 1). The difference in size allowed the fluorite to move freely within the void. Also present in the void and surrounding the fluorite crystal were an aqueous liquid and a small gas bubble. Because the cavity was an octahedron, a shape not related to quartz morphology, it is assumed that the fluorite was originally much larger and defined the shape of the void while in that larger state. Also observed was a secondary healed crack that broke from the surface of the quartz to the void while it was still in the growth environment. This crack allowed fluids that were not in equilibrium with the fluorite to partially dissolve it before the crack healed, trapping the much smaller fluorite remnant in the void. Mobile inclusions in gems such as this example are rare and fascinating to observe.
