Mineral
Hemimorfita
Zn₄Si₂O₇(OH)₂·H₂O · Silicatos
Hemimorphite is a hydrated zinc hydroxy-silicate that crystallises in the orthorhombic system and occurs as a secondary mineral in oxidation zones of zinc deposits.
It forms as a secondary zinc mineral in the oxidation zones of sulphides. It occurs as botryoidal masses, stalactitic forms and tabular crystals. It also forms fans and rosettes.
At Mapimí it occurs in cavities lined with colourless, vitreous crystals. There it is associated with mimetite, which may appear as small yellow bow-tie aggregates. At Santa Eulalia it shows bluish tones caused by copper inclusions, which are uncommon. It is valued for its light blue colour and texture.
Etymology
The name "hemimorphite" comes from the Greek "hemi" ("half") and "morphe" ("form"), in allusion to the unequal development of the ends of the crystal. The name "mimetite" derives from the Greek "mimetes" ("imitator"), for its similarity to pyromorphite.