Definitions of asbestos-related mineralogical terminology

Our plain-English summary of Definitions of asbestos-related mineralogical terminology, by Tibor Zoltai, Ann G. Wylie (1979).

The study

• Authors: Tibor Zoltai, Ann G. Wylie
• Published: Annals of the New York Academy of Sciences, vol. 330, pp. 707-709 (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 is not a study of people or exposure. It lists asbestos-related mineral definitions, published in 1979 by authors from two university geology departments. The authors explained how minerals, mineral series (such as cummingtonite-grunerite) and mineral groups (such as the amphiboles) are named. They described how one mineral can grow in different habits: the asbestiform variety of actinolite was once named asbestos, while its massive microcrystalline variety is nephrite, a type of jade. They wrote that amphiboles cleave into long fragments that can easily be mistaken for asbestos fibers in the electron microscope. They also wrote that at microscopic levels asbestiform fibers, needle-shaped crystals and cleavage fragments may be impossible to tell apart. They defined asbestiform as a fibrous habit with extreme aspect ratios, easily separable and flexible fibers, and higher tensile strength than crystals in other habits of the same mineral. They defined asbestos as a collective term for asbestiform varieties of silicate minerals. They called this restriction possibly questionable mineralogically. However, they wrote that non-silicate fibers may justifiably be excluded from the asbestos category in public health studies.

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 mineralogical definitions (not a study of people, animals or exposure)
• Main results:
  • Some minerals form series that are named by their end members. One example given is the cummingtonite-grunerite series. In the actinolite-tremolite series, tremolite is the pure magnesium end member.
  • A mineral can grow in different habits, some of which have variety names. The asbestiform variety of actinolite was once believed to be a distinct mineral and was named asbestos. Other actinolite varieties are called mountain leather and byssolite.
  • The massive microcrystalline variety of actinolite is known as nephrite, one of the two types of jade.
  • Because of their cleavage pattern, amphibole fragments at all sizes resemble needle-shaped (acicular) crystals. In the electron microscope they can easily be mistaken for asbestos fibers.
  • Any needle-like particle with parallel edges may be called a fiber. At microscopic levels it may not be possible to distinguish asbestiform fibers, acicular crystals and needle-like cleavage fragments.
  • Asbestiform was defined as a special fibrous habit. Its fibers have extreme aspect ratios and are easily separable and flexible. They also have higher tensile strength than crystals in 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 restricting asbestos to silicate minerals may be questionable from the mineralogical point of view, because nonsilicate minerals may also crystallize in fibrous habit.
• The authors' conclusion: The authors expect the properties of non-silicate fibers to differ in magnitude from those of asbestiform silicates. On that basis, they suggested that such fibers may justifiably be excluded from the category of asbestos in public health studies.

Topics

Medical terms in this study, explained in our Lexicon: Cummingtonite-Grunerite, Amphibole Group, Habit, Asbestiform, Actinolite, Cleavage Fragment, Fibrous Habit, Aspect Ratio (Length-to-diameter ratio).

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