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The Mineral Anglesite

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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

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:

  • 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.

FAQ (Frequently Asked Questions)

Q1. What does Mineral Really Mean?

Answer: Geologically, a mineral is a naturally occurring, homogeneous, solid substance that contains a crystalline atomic structure. Crystallinity in a mineral means that a mineral contains a definite and limited range of composition, and that the composition can be described as a chemical formula. Some explanations of minerals give them as inorganic substances, however both graphite and diamonds are considered minerals, and moreover are primarily made up of carbon, which would make them organic. Remember that, the essential components that make something a mineral are occurring naturally, and the clear-cut crystal structure, that is pronounceable as a chemical formula. Rocks that fail to fulfill these criteria are known as amorphis - not possessing a definite structure or expressible chemical formula. Some elements that form naturally and are minerals are arsenic, bismuth, copper, gold, platinum, silver, and sulphur.

Q2. Are There Any Similar Distinguishing Minerals?

Answer: Following are the minerals that are though not angelsite but consist of certain properties that make them somewhat similar to the former mineral:

  1. Barite - Lacks adamantine luster.

  2. Celestine - lighter in weight, lacks adamantine luster.

  3. Cerussite – Swooshes in hydrochloric acid, crystals commonly twinned.

  4. Phosgenite – often difficult to distinguish, but forms in different crystals, and is sectile and unbreakable