The Mineral Anglesite
Having a chemical formula PbSO4, anglesite mineral is a secondary lead mineral which always occurs through the modification of lead sulfides, principally Galena. Anglesite crystals may consist of impurities of Galena, providing a specimen a gray to black color. In some regions of source, Anglesite occurs as a pseudomorph after Galena, rendering the crystals a false isometric form. Gray and black banding exists in some giant Anglesite specimens that can be observed when a specimen is either sliced or polished.
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Angle Site Specimens
Anglesite specimens sliced or polished may even consist of unaltered Galena in the center, which remains constant to Anglesite when the outer layers are changed. An amber-red Anglesite from Morocco has been artificially colored by submerging light yellow crystals in bleach.
Physical Properties of Anglesite
Chemical Properties of Anglesite Mineral
Identifying Characteristics
With a SG of 6.30 to 6.39, the mineral is placed among the densest gem materials. Testing for SG can generally differentiate it from other gems of similar appearance. But, two other rarely faceted collector’s tones consist of a comparable array of colors, hardness, and SG. In the same vein as anglesite, cerussite and phosgenite can also be colorless as well as yellowish, grayish, greenish or white. Their fluorescence under ultraviolet light can also seem to be yellowish.
Although angle sites with pale colors can exhibit high dispersion and brightness, they’re very complicated to cut and not recommendable to wear. Faceted pieces are true rarities, barely spotted except in very exquisite, complete gem collections.
Synthetics
Laboratories have synthesized anglesite for the purpose of geological research. However, there is no apparent use of this substance for jewelry making purposes.
Enhancements
In the early 1980s, amber-red anglesites crystals from Touissit, Morocco were discovered to be an outcome of bleaching colorless and pale yellow specimens. This treatment yielded surface-deep colors. Only submergence in a bromide-water solution is able to reverse this coloration.
Sources of Anglesite Occurrence
Although many localities across the globe can potentially produce gemmy crystals, only a few contain the capacity of yielding colorless and pale brown crystal specimens.
Touissit, Morocco generates gem crystals in massive sizes for this species.
Tsumeb, Namibia yields huge transparent yellowish crystals and, often, gemmy colorless crystal specimens.
Other Notable Gem-Quality Sources are as below:
United States; Arizona; Chester County, Coeur d’Alene district, Idaho; New Mexico; Pennsylvania; Tintic, Utah.
Australia; Wales, Broken Hill, N.S.W., Brazil; Germany; Mexico; Russia; Scotland, Sardinia; Slovenia; Dundas, Tasmania; Tunisia; England, United Kingdom.
Anglesite Stone Sizes
Faceted anglesites essentially range from 1 to 6 carats. Seldom does this substance occur massive enough to cut anything larger than this. However, some rough, remarkably from Morocco and Namibia, has produced 100+ carat gems. One such stone from Tsumeb, notably of 300 carats, broke during cutting!
Care of Anglesite Crystal
Anglesites majorly consist of lead. When cutting this mineral, avoid ingesting or inhaling splinters and make sure to wash your hands. Jewelry use is not advisable.
Anglesite Uses
Some Uses of Anglesite Mineral are in:
Batteries
Ammunition
Radiation
Plumbing
sound absorber
shield of x-rays
Paint pigment, glass and insecticides.
Fun Facts
Anglesite is a lead mineral, quite rare in occurrence.
It contains bladed or tabular crystals, having a mohs hardness of 2.5-3 and SG of 6.3.
It is a secondary mineral, essentially occurring in the oxidation zone of a lead sulfide.
This anglesite mineral contained several lead crystals on its surface.
The mineral is associated with galena, barite, cerussite, and liminote
Anglesite crystal is named for its type locality at the Parys Mine, on the Island of Anglesey, Wales (UK).
Pbso4 mineral can also be found in black color due to Galena impurities, which can also induce it to be banded gray and black.
Where it occurs massively, it caters as a lead ore.
Anglesite’s fire or dispersion is equivalent to that of diamond (0.044).
If properly faceted, this crystal can also exhibit magnificent brilliance.
Due to angelsite’s hardness of 2.5 to 3 and good cleavage, cutting demands great care.
FAQs on Anglesite
1. What exactly is Anglesite?
Anglesite is a lead sulfate mineral with the chemical formula PbSO₄. It is known as a secondary mineral because it forms when a primary lead ore, usually Galena, gets altered by natural processes. Anglesite often appears as white, grey, or yellowish crystals and is important as a source of lead.
2. What are the main uses of Anglesite?
The main use of Anglesite is as a minor ore of lead. While Galena is the primary source, Anglesite is also valuable where it is found in large quantities. Additionally, due to its brilliant crystal forms and high lustre, well-formed Anglesite specimens are highly sought after by mineral collectors.
3. What is the chemical formula for Anglesite?
The chemical formula for Anglesite is PbSO₄. This indicates that each molecule of the mineral consists of one lead atom (Pb), one sulfur atom (S), and four oxygen atoms (O), forming the compound lead sulfate.
4. Where in the world is Anglesite typically found?
Anglesite is found in the upper, oxidized parts of lead ore deposits across the globe. Some famous locations where high-quality Anglesite crystals are found include:
- Monteponi in Sardinia, Italy
- Tsumeb, Namibia
- Leadville, Colorado in the USA
- Various sites in Morocco and Australia
5. How does Anglesite actually form in nature?
Anglesite forms through a natural chemical process called oxidation. It starts with Galena (lead sulfide, PbS), the primary lead ore. When Galena is exposed to oxygen-rich water or air, it undergoes a chemical reaction that transforms it into lead sulfate (PbSO₄), which is Anglesite. This is why it's called a secondary mineral—it forms from the alteration of another mineral.
6. Why is Anglesite considered an ore of lead if Galena is the main source?
An ore is any mineral from which a metal can be profitably extracted. Anglesite is considered an ore because it contains a very high percentage of lead by weight (about 68%). Even though Galena is more common, Anglesite is often found with it in the upper layers of a mine. Mining both minerals together increases the total yield of lead from the deposit, making it economically valuable.
7. How can you tell Anglesite apart from similar-looking minerals like Barite?
Although they can look alike, the easiest way to distinguish Anglesite is by its high density. If you hold a piece of Anglesite, it will feel unusually heavy for its size compared to minerals like Barite or Celestine. Anglesite also has a brilliant, almost diamond-like (adamantine) lustre, which is typically much duller in similar minerals.
8. Is it possible to use Anglesite as a gemstone in jewellery?
While Anglesite can form beautiful, transparent crystals, it is not suitable for jewellery for three main reasons. Firstly, it is very soft and can be easily scratched. Secondly, it is brittle and can break with impact. Most importantly, it is a lead-based mineral and is toxic if dust from it is inhaled or ingested, making it unsafe for wearing.
