494 - Hemimorphite and Limonite

ID	494
Mineral	Hemimorphite Limonite
Location	Potosí Mine - Francisco Portillo - Chihuahua - Mexico
Fluorescence	LW-UV: close SW-UV: close
Mindat.org	View Hemimorphite information at mindat.org View Limonite information at mindat.org

ID	1860
Long ID	1:1:1860:5
Formula	`Zn₄(Si₂O₇)(OH)₂ · H₂O`
IMA Status	0 1
Other Occurrences	Secondary mineral in the weathered portions of zinc deposits.
Industrial	Ore of zinc.
Discovery Year	1853
Diapheny	Transparent,Translucent
Cleavage	Perfect on {110}, poor on {101}, {001} rare
Tenacity	brittle
Colour	Colorless, white, pale blue, pale green, gray, brown
Hardness (min)	4.5
Hardness (max)	5.0
About the name	Named in 1853 by Adolph Kenngott in allusion to the hemimorphic morphology of the crystals. Many names were previously assigned to this species, including calamine. Hemimorphite was chosen by the International Mineralogical Association, over calamine, in 1962.
Streak	White
Crystal System	Orthorhombic
Cleavage Type	Perfect
Fracture type	Irregular/Uneven,Sub-Conchoidal
Morphology	Thin tabular crystals, sheaf-like or fan-like aggregates, stalactitic, mammillary, botryoidal.
Twinning	On {101} rare
UV	May be bluish under SW UV.
Thermal Behaviour	Heated in a closed tube, it decrepitates, whitens, and gives off water. Before the blowpipe, almost infusible (F = 6).
key_elements	0
shortcode_ima	Hmp

ID	2402
Long ID	1:1:2402:6
Description	Currently used as a field-term for unidentified massive hydroxides and oxides of iron, with no visible crystals, and a yellow-brown streak. 'Limonite' is most commonly the mineral species goethite, but can also consist of varying proportions of lepidoc...
Diapheny	Opaque
About the name	Named in 1813 by Johann Friedrich Ludwig Hausmann from the Greek λειμών for meadow alluding to its common occurrences in bogs.

Hemimorphite and Limonite