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.
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
|
Elements |
Elucidation |
|
Composition |
Lead sulfate |
|
Rock Type |
Metamorphic |
|
Color |
Colorless to white, most commonly tinted grey. Sometimes green, yellow or blue; completely colorless in transmitted light. |
|
Group |
Sulfates; Anhydrous Sulfates |
|
Streak |
Colorless |
|
Mohs Hardness |
2½ – 3 |
|
Occurrence Environment
|
Anglesite is a secondary mineral occurring in eroded lead deposits. |
|
Transparency |
Transparent, Translucent, Opaque in think splinters |
|
Luster |
Adamantine, Resinous, Vitreous |
|
Density (Measured) |
6.37 – 6.39 g/cm3 |
|
Density (Calculated) |
6.36 g/cm3 ; 2,1 – basal ; 3,1 – prismatic |
|
Specific Gravity (SG) |
6.4 |
|
Tenacity |
Brittle |
|
Cleavage |
Distinct/Good |
|
Fracture |
Conchoidal |
|
Parting |
Twin gliding and translation gliding forms |
|
ID Marks |
Often fluorescent light yellow in shortwave UV Light |
|
Highlighting Features |
Unusual heaviness adamantine luster mineral linkages untwined crystals |
Chemical Properties of Anglesite Mineral
|
Elements |
Elucidation |
|
Chemical Formula |
PbSO4 |
|
IMA Formula |
Pb(SO4) |
|
Elements listed |
O, Pb, S |
|
Common Impurities |
Ba, Cu |
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:
Fun Facts
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Anglesite is a lead mineral, quite rare in occurrence.
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It contains bladed or tabular crystals, having a mohs hardness of 2.5-3 and SG of 6.3.
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It is a secondary mineral, essentially occurring in the oxidation zone of a lead sulfide.
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This anglesite mineral contained several lead crystals on its surface.
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The mineral is associated with galena, barite, cerussite, and liminote
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Anglesite crystal is named for its type locality at the Parys Mine, on the Island of Anglesey, Wales (UK).
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Pbso4 mineral can also be found in black color due to Galena impurities, which can also induce it to be banded gray and black.
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Where it occurs massively, it caters as a lead ore.
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Anglesite’s fire or dispersion is equivalent to that of diamond (0.044).
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If properly faceted, this crystal can also exhibit magnificent brilliance.
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Due to angelsite’s hardness of 2.5 to 3 and good cleavage, cutting demands great care.