Asbestos Fibers and Other Elongate Mineral Particles: State of the ...

Table 2. Definitions of specific minerals (Continued)
148
Glossary of Geology, 5th ed.
[American Geological Institute 2005] Leake et al. [1997] NIOSH [1990a]
Dictionary of Mining,
Mineral, and Related Terms
[U.S. Bureau of Mines 1996]
[Note: Footnotes identify the Primary
Source Citation for the definition]
Term
Crocidolite is from the fibrous
habit of the mineral riebeckite
and is in the mineral series
glaucophane-riebeckite, in
which both asbestiform and
nonasbestiform habits can occur.
This mineral type is commonly
referred to as “blue asbestos.”
An asbestiform variety of riebeckite;
forms lavender-blue, or indigo-blue, or
leek-green silky fibers and massive and
earthy forms. Also spelled krokidolit.
Crocidolite An asbestiform variety of
riebeckite; forms lavender-blue,
or indigo-blue, or leek-green silky
fibers and massive and earthy
forms; suited for spinning and
weaving. Also spelled krokitolit.
A monoclinic Mg-Fe-Mn-Li
amphibole: Mg7Si8O22(OH) 2;
may also contain divalent iron
but with Mg/(Mg+Fe2+ ) ≥ 0.50
(otherwise it is grunerite)
A dark green, brown, gray, or beige monoclinic
member of the amphibole group:
(Mg,Fe2+ ) 7Si8O22(OH) 2. It is dimorphous with
anthophyllite, and typically contains calcium and
manganese. Cummingtonite occurs in metamorphosed
ironstone, mafic and ultrabasic rocks,
some dacites and rhyolites, and as a component
of uralite. Its iron-rich variety is grunerite.
Cummingtonite A monoclinic mineral,
(Fe,Mg) 7Si8O22(OH) 2; amphibole
group; has Mg/(Mg+Fe2+ ) = 0.30
to 0.69; prismatic cleavage; may be
asbestiform; in amphibolites and
dacites; fibrous varieties (amosite,
magnesium rich, and montasite,
iron rich) are used as asbestos.
Erionite A white hexagonal zeolite mineral. [Ed. Note:
Designated as Erionite (Ca,K,Na) depending
on the dominant cation substitution.
A monoclinic calcic amphibole:
Ca2Fe2+ 5Si8O22(OH) 2; may
also contain magnesium but
with Mg/(Mg+Fe2+ ) ≤ 0.5
(otherwise it is actinolite).
A green-black monoclinic mineral
component representing a theoretical
end-member of the amphibole group:
Ca2Fe2+ 5Si8O22(OH) 2. Syn: ferrotremolite.
Ferroactinolite A monoclinic mineral,
Ca2(Fe2+ ,Mg) 5Si8O22(OH) 2];
amphibole group; has Mg/
(Mg+Fe2+ ) = 0 to 0.50;
forms a series with tremolite
and actinolite. Formerly
called ferrotremolite.
See footnotes at end of table. (Continued)
NIOSH CIB 62 • Asbestos