Rickturnerite
Chemical formula: Pb<sup>2+</sup><sub>7</sub>O<sub>4</sub>[Mg(OH)<sub>4</sub>](OH)Cl<sub>3</sub>
Rickturnerite is an extremely rare lead and magnesium mineral of intense orange-red color, known from only one locality in the world.
Description
## Characteristics Rickturnerite is a secondary lead, magnesium, chlorine, and oxygen mineral, forming characteristic thin coatings and crusts. It occurs as very small, subhedral (partially formed) or anhedral (unformed) crystals, not exceeding 100 micrometers in size. Its most distinguishing feature is its intense, bright color, ranging from orange-red to red. ## Physical Properties This mineral is characterized by a adamantine to resinous or greasy luster. It is translucent. Its Mohs hardness has not been determined due to the small size of the crystals. The density, calculated based on chemical composition and unit cell parameters, is 6.93 g/cm³, but has not been empirically measured. ## Colors and Varieties Rickturnerite occurs in uniform, bright shades of red and orange. No color or commercial varieties are known. ## History and Name The mineral is named in honor of Dr. Rick W. Turner (b. 1942), a geologist working for the British Columbia Geological Survey in Canada. It was officially recognized by the International Mineralogical Association (IMA) in 2010. The type locality (and only known) is a small, unnamed lead, zinc, and silver ore occurrence near the Blue Bell Mine in Riondel, British Columbia, Canada. ## Uses Due to its extreme rarity and microscopic size, rickturnerite has no commercial or industrial applications. It is solely an object of scientific interest and a valuable acquisition for specialized micromineral collectors.
Diagnostic features
## Identification Identification of rickturnerite is based on its unique, bright orange-red color, specific occurrence environment (oxidation zone of Pb-Zn deposits in contact with slag), and co-occurring minerals. Due to the microscopic size of the crystals, definitive confirmation of identity requires advanced analytical methods such as X-ray diffraction (XRD) or X-ray microanalysis (EDS). ## Distinguishing from Similar Minerals Rickturnerite can be confused with other secondary lead minerals of similar color, such as minium (lead oxide) or crocoite (lead chromate). However, it is distinguished by its specific chemical composition (presence of magnesium and chlorine), tetragonal crystal form, and mineral paragenesis. Unlike the often well-formed, prismatic crystals of crocoite, rickturnerite forms only microscopic, anhedral grains and coatings. ## Crystal Forms It forms coatings and thin layers composed of anhedral or subhedral grains up to 100 μm in size. These crystals fill small voids and fissures in the rock.
Geological environment
## Genesis Rickturnerite is a secondary mineral with a very specific genesis. It forms in the oxidation zone of lead and zinc ore deposits. Its formation is a result of the reaction of waters percolating through historical metallurgical slag heaps with dolomitic marble. It is, therefore, an example of a mineral formed at the interface of natural processes and human (anthropogenic) activity. ## Mineral Associations It co-occurs with other secondary lead minerals such as paralaurionite, leadhillite, cerussite, and anglesite, as well as with relics of the primary ore, mainly galena. ## Localities The only confirmed locality of rickturnerite in the world is its type locality near the Blue Bell Mine in Riondel, British Columbia, Canada.
Rarity
Extremely rare
Collector aspects
## Quality Criteria For such a rare micromineral, the main criterion for collector value is the richness of the specimen – i.e., the abundance and intensity of the rickturnerite coating on the rock matrix. Samples where the mineral contrasts with other well-defined associated minerals are highly prized. The size of the area covered by the mineral is more important than the size of individual, microscopic crystals. ## Popular Localities All known specimens come from a single location – the type locality in British Columbia, Canada. This mineral is practically unavailable on the open market and primarily goes to institutional collections and the most specialized collectors of rare minerals.
Care and storage
## Cleaning Rickturnerite specimens are extremely delicate and should be handled with the utmost care. The only safe method for dust removal is to use compressed air from a safe distance. Any contact with water, cleaning solutions, and brushes, which could irreversibly damage the microscopic crystals, should be avoided. ## What to Avoid This mineral, as a complex hydroxychloride, is likely sensitive to acids and other chemicals. It should be protected from moisture, sudden temperature changes, and direct, prolonged exposure to sunlight, which can cause fading. Avoid vibrations and shocks. ## Storage It is recommended to store specimens in stable conditions, preferably in a sealed, padded micromount box, which protects against dust, mechanical damage, and humidity changes. Display should be in a closed cabinet, away from heat and light sources.