Hemimorphite, is a sorosilicate mineral which has been mined from days of old from the upper parts of zinc and
lead ores, chiefly associated with smithsonite. It was often assumed to be the same mineral and both were classed
under the same name of calamine. In the second half of the 18th century it was discovered that there were two
different minerals under the heading of calamine - a zinc carbonate and a zinc silicate, which often closely
resembled each other.
The silicate was the more rare of the two, and was named hemimorphite because of the hemimorph development of
its crystals. This unusual form, which is typical of only a few minerals, means that the crystals are terminated by
dissimilar faces. The crystal structure produces a different termination at each end of the crystal. The crystal base is
formed as a pedion (a crystal form having only a single face, without a symmetrical equivalent) while the visible tip is
formed like the point of a pyramid. Some specimens show strong green fluorescence in shortwave ultraviolet light
(253.7 nm) and weak light pink fluorescence in longwave UV.
Specimens of hemimorphite are found in two very different forms. One form produces glass like, clear or white, thin,
bladed crystals, often well-formed showing many crystal faces. Many times these crystals are arranged in fan
shaped aggregates. The other form produces a blue to blue-green botryoidal crust that resembles smithsonite or
prehnite. For a collector both forms are a must in their mineral collections.
information courtesy of http://en.wikipedia.org/wiki/Hemimorphite
|Superb Old Stock Hemimorphite on Limonite from Durango, Mexico
From our Personal Collection comes this rare Old Stock specimen of exceptionally clearlayered plate of
Hemimorphite acicular crystals on Limonite. This specimen came from Durango, Mexico in the 1960's.
Specimens this nice are rarely found. The crystals are amazing and cover the surfaces of the specimen in a
crystalline shroud. We procured this specimen from an old time rockhound while we were in Nevada.
This specimen weighs 6 oz or 0.38 lbs (172g) and measures 4.4 x 2.4 x 1.5 inches (11.2 x 3 x 3.8cm)
|Item # HEM07108472
Superb Old Stock
Hemimorphite on Limonite
from Durango, Mexico