mineral
Botryoidal hemimorphite on matrix
Hemimorphite, Zn₄Si₂O₇(OH)₂·H₂O, likely with associated quartz or calcite
AI-generated identification · may be incorrectPale blue to turquoise, botryoidal and stalactitic crystal growths with vitreous to pearly luster; Mohs hardness 4.5–5, orthorhombic structure, uneven fracture, and specific gravity about 3.4–3.5. The porous gray-brown host is likely limonite or altered carbonate matrix.
Identified More mineral →
Explore Botryoidal hemimorphite on matrix in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Pale blue to turquoise, botryoidal and stalactitic crystal growths with vitreous to pearly luster; Mohs hardness 4.5–5, orthorhombic structure, uneven fracture, and specific gravity about 3.4–3.5. The porous gray-brown host is likely limonite or altered carbonate matrix.
Formation & geological history
Forms as a secondary zinc-ore mineral in oxidized zones above sulfide deposits, commonly replacing or coating limestone and limonite. These specimens typically formed during relatively recent supergene weathering, rather than representing a distinct ancient rock age.
Uses & applications
Collected as a decorative mineral specimen and occasionally cut into cabochons; it has little structural or industrial use. Fine vivid-blue pieces can command substantial prices.
Geological facts
Its rounded, grape-like (“botryoidal”) surfaces and blue color are diagnostic, though turquoise, smithsonite, and chrysocolla can look similar. Hemimorphite is commonly associated with smithsonite, willemite, calcite, and limonite.
Field identification & locations
Major localities include Mina Ojuela, Mapimí, Mexico; Upper Silesia, Poland; China; Namibia; and Arizona. Confirm with hardness, high density, lack of strong cleavage, and ideally laboratory testing; avoid acid or destructive tests on valuable specimens.
