Name/Title
HemimorphiteEntry/Object ID
2013.1.30Description
Chemical Composition: SiO2
Crystal System: Triclinic System
Description: Common Name: Hemimorphite
Chemistry: Zn4Si2O7(OH)2·H2O
Group: Silicates
Location: Santa Eulalia, Chihuahua, Mexico
Description: This is a small specimen that has a very distinct sprayed shape. The color is a dirty pink with some white also.
Physical Charateristics:
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. Hemimorphite most commonly forms crystalline crusts and layers, also massive, granular, rounded and reniform aggregates, concentrically striated, or finely needle-shaped, fibrous or stalactitic, and rarely fan-shaped clusters of crystals.
Some specimens show strong green fluorescence in shortwave ultraviolet light (253.7 nm) and weak light pink fluorescence in longwave UV.
Fracture: Conchoidal
Hardness: 8 Topaz
Luster: Glassy
Rock Type: Sedimentary
Specific Gravity: 2.68-2.72
Streak: WhiteCollection
RAGM Mineral CollectionDimensions
Width
1-1/4 inDepth
1-3/4 inLength
3-1/4 inLocation
Location
Display Case
FS-4Room
Frieda Smith HallBuilding
Crater Rock MuseumCategory
PermanentDate
August 18, 2023
