THE MINERAL DESCLOIZITE

Chemistry: PbZn(VO4)(OH) , Lead Zinc Vanadate Hydroxide
Class: Phosphates
Group: Descloizite
Uses: As a minor ore of lead and zinc and as mineral specimens
Specimens

Descloizite is the namesake of the descloizite group of minerals. The group is composed of rather rare members of which descloizite is its most common member. Descloizite is an end member of a series composed of the mineral mottramite. Mottramite is the copper rich end member while descloizite is the zinc rich member. Both minerals usually contain significant percentages of both elements and are rarely pure. Descloizite can form nice well shaped crystals that have a nice luster and striking color. Its rarity and attractiveness are the reason for the typically high prices one would expect to pay for a fine specimen.

PHYSICAL CHARACTERISTICS:

Color is typically brown to reddish brown to black also yellow to orange with increase in copper content.
Luster is greasy.
Transparency: Crystals are transparent to opaque.
Crystal System is orthorhombic; 2/m2/m2/m
Crystal Habit is typically in small, flat platelets that have a rounded triangular shape or in a pyramidal form, also in tiny druzy crusts and stalactitic masses.
Cleavage is none.
Fracture is conchoidal to uneven.
Hardness is 3 to 3.5.
Specific Gravity is approximately 6.2 (very heavy for translucent minerals)
Streak is brownish red to orange to yellow.
Associated Minerals are wulfenite, vanadinite, mottramite, pyromorphite, and cerussite.
Other Characteristics: Some crystals can appear arrowhead shaped.
Notable Occurrences include Tsumeb, Nambia; Zambia; Germany; Pinal County, Arizona, and Grant County, New Mexico; U.S.A.
Best Field Indicators are color, crystal habit, localities and density.