GIBBSITE, XIANGHUALING MINE, CHINA
Gibbsite is a very rare aluminum hydroxide mineral. One of our favorite Chinese wholesale dealers obtained a good selection of these direct from the mine, and air shipped us a large box of the best specimens from a new find in the summer of 2009. The color on this lot is a lovely turquoise- to greenish-blue and the gibbsite is formed in lustrous and translucent botryoidal aggregates. This specimen comes from the Xianghualing mine, Xianghualing Sn-Polymetallic Ore field, Linwu Co., Chezhou prefecture, Hunan province, China. Previously, material from here came to market in the early days of Chinese mineral exports in the mid 1990s, and again in a trickle in 2006.
GIBBSITE, XIANGHUALING MINE, CHINA
Gibbsite is an important ore of aluminum and is one of three minerals that make up the rock bauxite. Bauxite is often thought of as a mineral but is really a rock composed of aluminum oxide and hydroxide minerals such as gibbsite, boehmite, AlO(OH) and diaspore, HAlO2, as well as clays, silt and iron oxides and hydroxides. Bauxite is a laterite, a rock formed from intense weathering environments such as found in richly forested, humid, tropical climates.
GIBBSITE, XIANGHUALING MINE, CHINA
PHYSICAL CHARACTERISTICS:
* Color is white or colorless with shades of gray, blue and green.
* Luster is vitreous to dull; cleavage surfaces have a pearly luster.
* Transparency Crystals are translucent and rarely transparent.
* Crystal System is monoclinic; 2/m.
* Crystal Habit is usually massive but rare crystals are found in flattened tabular crystals. In many bauxite specimens, gibbsite is found in a pisolitic habit. Also found as botryoidal encrustations, concretionary, stalactitic and foliated masses.
* Cleavage is perfect in one direction, basal.
* Fracture is uneven.
* Hardness is 2.5 – 3.5
* Specific Gravity is 2.4 (slightly below average)
* Streak is white.
* Other Characteristics: When breathed on, gibbsite gives off a noticeable clay smell.
* Notable Occurrences include Vogelsberg, Germany; Gant, Hungary; Les Baux, France; Lavrion, Greece; Guyana and Arkansas, USA.
* Best Field Indicators are crystal habits, hardness, smell and associations.
Click here to visit the GIBBSITE gallery on our website, featuring several of these very rare mineral specimens.
GIBBSITE, XIANGHUALING MINE, CHINA
