1 / 17

A Survey of Fibrosity of Fibrous Amphiboles

Learn about the differences between asbestiform and non-asbestiform minerals through macroscopic and microscopic properties. Find out how to quantify these differences using fibrosity measurement techniques. Discover insights from the Fibrosity Chart and Index of Mineral Properties, highlighting the variability in fibrosity among actinolite, tremolite, and anthophyllite. Uncover correlations between fibrosity index, mineral chemistry, and fiber characteristics in this informative study. Reframe your classification of amphibole samples based on fibrosity index rather than simply asbestiform or non-asbestiform.

jennefer
Download Presentation

A Survey of Fibrosity of Fibrous Amphiboles

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. A Survey of Fibrosity of Fibrous Amphiboles Larry S. Pierce Fiberquant Analytical Services Phoenix, AZ lspierce@fiberquant.com

  2. Asbestiform vs. Non-asbestiform • mineral habit is a macroscopic property (naked eye, hand loupe or stereoscope) • microscopic properties (PLM, SEM, TEM) of asbestiform minerals vary • old timer’s “tremolite asbestos, but brittle” indicates that >100 years ago, it was recognized that all that is asbestiform is not the same

  3. Both are asbestiform actinolite • 1st is straight at any magnification; shiny clear-white under stereoscope; kind of chunky @100x though fibrous; not much brooming • 2nd is flexible; dead-white under stereoscope; can hardly be seen @100x; lots of brooming

  4. How to Quantify the Differences • Average Aspect Ratio • Graph of Aspect Ratio Frequency • Quantitative Fibrosity Measurement (Chatfield 2010, 2011)

  5. Fibrosity procedure Chatfield (Beard Conference, 2010): • grind sample in mortar & pestle • (fractional extraction) • Suspend & prepare TEM drop mounts • measure L & W ~200 fibers >5 um long @10,000x • plot aspect ratio vs fiber width using log/log axes

  6. Fibrosity Chart – very fibrous

  7. Fibrosity Chart – not so fibrous

  8. Index of mineral properties • Fibrosity chart procedure is intuitively satisfying – each fiber is plotted • No matter how asbestiform/non-asbestiform, there tend to be at least a few data points outside/inside the 20:1 box • Good mineral property index – every example seems to be on scale • Let’s define F.I. = % fibers inside the box • What variation in F.I. is normal? examples of actinolite, tremolite and anthophyllite

  9. Cast of Characters

  10. Conclusions • Asbestiform tremolite, actinolite and anthophyllite present a broad and continuous range of fibrosity index • Little or no correlation of fibrosity index to chemistry • Little or no correlation to mean fiber length • Correlation to mean width • Correlation to mean aspect ratio

  11. Moral of the Story • Instead of referring to an amphibole sample or deposit as merely asbestiform or non-asbestiform, we should rather specify how asbestiform (Fibrosity Index or Confirmed Asbestos or something similar) • http://www.fiberquant.com/johnson2011.htm (photos/data)

More Related