Asbestos Asbestos ► Certain minerals that have a fibrous habit Asbestos ► Uses? Insulation Fireproofing materials Brake and clutch linings Construction materials Filters etc Asbestos ► Today’s lab This will reinforce optical skills Show you how understanding mineralogy can be important to public health and current issues Asbestos varies depending on the ► Definition organization: Mineralogist- fibrous material with a length width ration of at least 10:1 OSHA( ): a mineral material Occupational Safety and Health Administration composed of any of the six silicate minerals (table 1) with a length width ration of 3:1 Asbestos ► Riebeckite – crocidolite (blue) amphibole ► Grunerite – Amosite (brown) amphibole ► Actinolite/Tremolite – Byssolite amphibole You have seen this in lab before ► Serpentine – Chrysotile (white) sheet silicate Asbestos ► Serpentine (white) It is a sheet silicate, how is it fibrous? ►Two sheets make up this silicate Mg2+ (9.36 A) Si4+ (9.05 A) These two share an Oxygen in their bonding This causes the chrysotile to form in tightly rolled sheets that make long flexible fibers. ► Seen only in HRTEM ► Figure 1 Chrysotile Atomic Structure Image Used from: http://www.ehponline.org/ members/1997/Suppl- 5/fubinifig4.GIF Asbestos ► Check out the hand samples in the room (away from the TA…safety is an issue here) DO NOT open the bags. The bags are around the mineral for a reason…and it’s not to keep it fresh for you to smell. Asbestos ► Microscope A B C ► When trying to determine which Asbestos these thin sections represent choose Crocidolite, Amosite, or Chrysotile ► More properties can be noted in the handout ► These properties will more than likely show up on the next great Quest ► Stereo Microscope (larger & more generalized view) Amosite, Crocidolite, and Chrysotile ► Match these to the thin sections & sketch them in the second circle Lab Cont. ► This lab is designed with dual work sessions in mind. You will do your part here and you will do the take home component. ► TURN IN the take home portion at or by the start of next lab for credit. Otherwise a late penalty will be assessed. ► This isn’t a tough lab. I expect the in lab portion as well as the take home portion to be neat and well done. The take home portion is to be typed in a word processor and printed to hardcopy.
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