Vote for your favorite mineral in #MinCup26! - Sphalerite vs. Anorthite Both zinc ore Sphalerite and calcium plagioclase feldspar Anorthite have perfect cleavage that will split cleanly if you hit them with a hammer, but only one can claim a larger split of your votes!
"The gonnardite/natrolite intergrowth, considered mesolite prior to 1988, has been verified from all Melbourne localities, and occurs as small, opaque white hemispheres and tufts composed of radiating fibres and prismatic needles. The individual groups have diameters up to 6 mm, though typically are 1 to 3 mm. The groups show a variety of lustre-chalky, sub-vitreous or silky- and the prismatic needles appear quite glassy when viewed through the microscope. The clusters that have been studied are radially zoned, presenting a compact gonnargite-rich core and a soft fibrous natrolite-rich outer zone."
Corporation quarries, Clifton Hill, Collingwood, City of Yarra, Victoria, Australia