A beautiful, large matrix specimen with a huge display face covered by sharp, metallic, acicular erythrite crystals. The matrix is HEAVY cobaltite-rich matrix, solid ore, several kilos. According to MINDAT: La Blanco is a small Co-Cu deposit close to the town of Freirina; mined on a small scale in the 19th century (Ref.: Maurizio Dini). It is the most likely source for this specimen because the original museum label (as big as the specimen in real life, so it could sit atop!) gives "San Juan, Chili" as the locality, and because that label also states the presence of "Asbolite." Asbolite is a now-discredited name for a "cobaltian wad" of interlocking acicular erythrite crystals. According to MINDAT, this is the only documented old locality which produced both erythrite and "asbolite." This specimen was given by the eminent researcher in the area, Dr. Domeyko, who sent many study samples to the Academy during its heyday. NOTE THAT BOTH PAS-182A AND PAS-182B WERE NUMBERED 5220 In THE SAME HAND, AT THE SAME TIME, indicating a common origin of the two specimens, though there is only one label. One assumes pieces were broken off for study on arrival at the museum. 5220 is a very early museum number dating to the late 1800s.