The compositional range of tremolite extends from [??][Ca.sub.2][Mg.sub.5][Si.sub.8][O.sub.22][(OH).sub.2] (where [??] = a vacancy) to [??][Ca.sub.2]Mg45Fe0+5[Si.sub.8][O.sub.22](OH)2, whereas actinolite
extends from [??] [Ca.sub.2]Mg[less than or equal to]5 [Fe.sup.2+.sub.[greater than or equal to]0.5] [Si.sub.8][O.sub.22][(OH).sub.2] to [??][Ca.sub.2][Mg.sub.2.5][Fe.sup.2+.sub.2.5] [Si.sub.8][O.sub.22][(OH).sub.2] (Leake et al., 1997; Hawthorne et al., 2012).
A similar chemical evolution was found by Kawakatsu and Yamaguchi (1987) from brown magnesiohornblende and magnesiohastingsite towards green magnesiohorblende and actinolite
in calc-alkaline plutonic rocks.
The first stage of alteration includes Na-Ca metasomatism (actinolite
+ titanite + epidote + calcite + albite [+ or -] scapolite [+ or -] quartz), which is characteristic of diorite-monzodiorite plutonic rocks (Figure 6(a)).
The rigid, stiff amphiboles are represented by five forms: crocidolite, amosite, anthrophylite, tremolite, and actinolite
. Crocidolite (blue asbestos) was commonly used in high temperature applications.
Signed by former Health Minister Suleiman Franjieh and former Environment Minister Akram Chehayeb, the law bars the importing of Crocidolite, Amosite, Anthophyllite, Actinolite
and Tremolite but allows a common asbestos called Crysotile, known as white asbestos.
The Chim Formation has been intruded by several porphyry aphosis which are commonly sericite, more rarely epidote and magnetite altered) Propylitic alteration in the Chim Formation shales is commonly green chlorite, with actinolite
and magnetite identified at the bottom of the hole.
A remarkable number of other species have also been identified as inclusions in Zambian emeralds, including actinolite
, tremolite, chlorite, dravite, apatite-(CaF), magnetite, hematite, quartz, fluorite, magnesite, siderite, dolomite, calcite, ankerite, niobium-rich rutile, pyrite, talc, zircon, barite, albite, lepidocrocite, glauconite, quartz, chrysoberyl, margarite, muscovite, biotite, brookite, tourmaline and chrysotile (Huong, 2008; Zwaan et al., 2005; Milisenda et al., 1999; Moroz and Eliezri, 1999; Graziani et al., 1983; Koivula, 1982, 1984; Gubelin and Koivula, 1986).
(4) The principal varieties of asbestos are chrysotile, a serpentine mineral, and crocidolite, amosite, anthophyllite, tremolite, and actinolite
, all of which are amphiboles.
(36.) Section 4 of the Asbestos Information Act of 1988 defines asbestos as chrysotile, amosite, or crocidolite, or in fibrous form, tremolite, anthophyllite, or actinolite
Gangue minerais consist of quartz, sericite, chlorite, actinolite
, tremolite, hornblende and calcite (Minfile 103P 023).