Definitions of Mineralogical Terminology

Our plain-English summary of Definitions of Mineralogical Terminology, by T. Zoltai, A.G. Wylie (1979).

The study

• Authors: T. Zoltai, A.G. Wylie
• Published: Annals of the New York Academy of Sciences p707-716 (1979)
• Type of article: Journal article
• Our copy: from Johns-Manville's own medical library. The article is still under copyright, so we describe it here rather than post it.

In plain English

This article was not a study of people or exposures but a set of definitions of mineralogical terms related to asbestos. The authors defined a mineral by its distinct crystal structure and chemical composition, and explained mineral series and mineral groups, with the amphiboles as an example of a group. They described how one mineral can grow in different habits. The asbestiform variety of actinolite was at earliest times believed to be a distinct mineral and was named asbestos. The authors wrote that amphiboles break along cleavage planes into elongated fragments, which can easily be mistaken for asbestos fibers in the electron microscope. At microscopic levels it may not be possible to tell asbestiform fibers from acicular crystals or needle-like cleavage fragments. They defined asbestiform as a fibrous habit with extreme aspect ratios, easy separability, flexibility and higher tensile strength. They defined asbestos as a collective term for the asbestiform varieties of various silicate minerals. They wrote that asbestos properties will develop gradationally in most cases.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: glossary of definitions of asbestos-related mineralogical terms (not a study of people, animals or samples)
• Main results:
  • A mineral was defined by its distinct crystal structure and chemical composition.
  • A mineral group was defined as minerals with identical or very similar crystal structures but different cations in secondary structural sites; amphiboles were given as an example.
  • Variety names for different habits of a mineral should not be confused with mineral names; the asbestiform variety of actinolite was at earliest times believed to be a distinct mineral and named asbestos.
  • Because of their cleavage, amphibole fragments at all sizes resemble acicular crystals and can easily be mistaken for asbestos fibers in the electron microscope.
  • A fiber was defined as an acicular single crystal or similarly elongated polycrystalline aggregate resembling organic fibers; at microscopic levels it may not be possible to distinguish asbestiform fibers, acicular crystals or needle-like cleavage fragments.
  • Asbestiform was defined as a special type of fibrous habit with extreme aspect ratios, easy separability, flexibility, and higher tensile strength than other habits of the same mineral.
  • Asbestos was defined as a collective mineralogical term for the asbestiform varieties of various silicate minerals; the authors wrote that nonsilicate fibrous minerals may justifiably be excluded from the category of asbestos in public health studies.
• The authors' conclusion: The authors stated that asbestos properties are due to structural variations and will develop gradationally in most cases.

Topics

Medical terms in this study, explained in our Lexicon: Crystal Structure, Amphibole Group, Habit, Asbestiform, Actinolite, Acicular, Cleavage Fragment, Fibrous Habit.

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