A fantastic unique piece! This was among the last of the fine vintage specimens remaining to be sold by the family of the late Tom Wiesner of Decatur, Illinois, a nationally noted mineral collector (particularly, but by no means limited to, fluorite). The specimen still carries his trademark white, tiny rectangular marking, with legible but tiny handwritten identification number, which he used to catalog his amazing collection. This piece was collected on March 27, 1971, and the identification card pictured is included with the purchase of the item.
There are a variety of other minerals as well on this specimen, but the label only indicates malachite and quartz, and they are indeed the two main component minerals. The quartz crystals are tiny and euhedral, with areas of acicular malachite around and under them, making the ones without the white mineralization coating look green. Although only Mexico is listed as a locale, it is order probably from Zacatecas, as several somewhat similar pieces viewed on mineral websites were from this area.
Measures approximately 3-1/2 x 3-1/2 x 1-1/2". Weighs 13.6 ounces.
Product code: Malachite and Quartz Specimen, from Mexico, Collected in 1971 - Ex. Tom Wiesner order Collection