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!
Initially identified as amblygonite, which turns out to be very rare in general. Usually isolated, blocky, subhedral to anhedral crystals found in the cleavelandite-rich quartz-plagioclase intermediate zone. Associated minerals are lepidolite, spodumene, colored tourmaline, quartz and cleavelandite. Some crude crystals, up to 3 inches ore more in diameter, have been collected. Several tons of montebrasite were removed at one time, prior to 1940. George Wilkes reported that five tons were taken out at one time, in the late 1930s, and thrown on the high dump. A fine white cleavage, five inches across, from this discovery, is in the Wesleyan University museum; the back of the specimen shows several contiguous crystal faces. There is also a four inch twinned crystal on display that Dick Schooner collected at the pollucite vein, halfway to the bottom of the pit. Quite a number of good crystals have come from the dumps.
Habit:
blocky anhedral
Colour:
white to pale grey
Quality for species:
Poor for species, only of interest for locality collectors. (#)
Strickland Quarry, Strickland pegmatite, Collins Hill, Portland, Middlesex County, Connecticut, USA