Amphibole group minerals are recognized to be among the natural occurring minerals that are considered to be potential environmental and health hazards. Amphiboles are chain silicate structures and under some conditions can take on asbestiform or fibrous habits. Compositionally and structurally, amphiboles can be understood as a hybrid of mica and pyroxene, and all the compositional variability of mica and pyroxene exists in amphiboles. The nomenclature of amphiboles is based on structure (orthorhombic or monoclinic) and chemical composition. Most of the compositional variability of amphiboles can be described by four major types of coupled cation substitutions and homovalent cation exchanges. Coupled cation-anion substitutions and homovalent anion exchanges cover the remaining compositions. These lead to 105 root (end member) names, most of which are rare. Chemical analysis, commonly by electron probe, is essential to assign an amphibole name. Most amphiboles can be named using stoichiometric estimates of ferric iron (Fe3+). Applying amphibole names in regulations poses a problem, because some names have been discredited or replaced (e.g., amosite => grunerite and crocidolite => riebeckite), and amphiboles from single localities (even single grains) may display chemical variation that requires multiple rootnames for different locations or even for a single grain—for example, classifying hazardous asbestiform amphiboles from Libby, Montana, United States, and Biancavilla, Sicily, Italy, requires three to six amphibole names. Furthermore, if Fe3+ is estimated using stoichiometry rather than determined, even more amphibole names could be applied to a single analysis. Analyzing fine-grained material believed to be amphiboles can be facilitated by familiarity with the geology and petrology of their source rocks, because this knowledge establishes a likely mineral assemblage and constrains the identities of minerals associated with a suspected amphibole composition. Examples of hazardous amphiboles examined in this paper suggest substitution mechanisms that affect the silicon-tetrahedral chains are limited in these amphiboles.
Author Information
Schumacher, John, C.
Dept. of Geology, Portland State University, Portland, OR, US
Domestic orders are delivered via United Parcel Service (UPS) or United States Postal Service (USPS). Transit
times average 3 to 5 business days. Please be aware that UPS will not deliver packages to Post Office Boxes.
International orders are delivered via courier post services which can be either a postal service, courier
service, or a combination of both. Standard Service is untraceable. Please allow 4-7 weeks for delivery.
Please be aware that carriers will not deliver packages to Post Office Boxes. Because of the variability of
customs processes and procedures in different countries, ASTM International cannot guarantee transit times to
international destinations. Customs duty and taxes are the responsibility of the consignee.
Shipping & Handling charges follow the rate schedule, below:
Order Total
Shipping & Handling Fee (US Domestic)
Up to $50.00
$18.72
$50.01 to $100.00
$20.80
$100.01 to $150.00
$29.52
$150.01 to $250.00
$39.09
$250.01 to $500.00
$56.25
$500.01 to $750.00
$76.42
$750.01 to $1000.00
$93.15
$1000.01 to $1500.00
$121.27
$1500.01 to $2500.00
$158.38
$2500.01 to $4999.00
$209.04
$5000.00 to higher
FREE
Order Total
Shipping & Handling Fee (International)
Up to $50.00
$68.72
$50.01 to $100.00
$70.80
$100.01 to $150.00
$79.52
$150.01 to $250.00
$89.09
$250.01 to $500.00
$106.25
$500.01 to $750.00
$126.42
$750.01 to $1000.00
$143.15
$1000.01 to $1500.00
$171.27
$1500.01 to $2500.00
$208.38
$2500.01 to $4999.00
$259.04
$5000.00 to higher
FREE
Shipping and Handling charges are approximate. Additional charges may be incurred if your order requires multiple shipments. This does not apply to complete sets and sections.
