Actinolite

Approved, 'Grandfathered' (first described prior to 1959)

Redefined by the IMA

1794

Redefined by IMA in 2012 (special procedure).

8/F.10-20

9.DE.10

9.DE.10

9 : SILICATES (Germanates)
D : Inosilicates
E : Inosilicates with 2-periodic double chains, Si₄O₁₁; Clinoamphiboles

14.23.2

14 : Silicates not Containing Aluminum
23 : Silicates of Fe, Mg, Ca

Vitreous, Silky

Transparent, Translucent

Green, green-black, grey-green, or black

Colourless, pale green to deep green in thin section.

White

5 - 6

Measured

Brittle

Distinct/Good
on {110}

on {100}

Splintery

3.03 - 3.24 g/cm³ (Measured)    3.07 g/cm³ (Calculated)

Biaxial (-)

n_α = 1.613 - 1.646 n_β = 1.624 - 1.656 n_γ = 1.636 - 1.666

Measured: 79° to 86°, Calculated: 78° to 82°

δ = 0.023

Moderate

r < v

Weak

X= pale yellow, yellowish green
Y= pale yellow-gree, green
Z= pale green, deep greenish blue

Ca, Fe, H, Mg, O, Si - search for minerals with similar chemistry

Mn,Al,Na,K,Ti

Monoclinic

2/m - Prismatic

B2/m

C2/m

a = 9.891 Å, b = 18.2 Å, c = 5.31 Å
β = 104.64°

a:b:c = 0.543 : 1 : 0.292

V 924.85 ų (Calculated from Unit Cell)

2

simple or lamellar, common parallel {100}; lamellar, less common parallel {001}

Radiation - Copper Kα

Data Set: Hartford County, Maryland, USA 168 Ehime Perfecture, Uma Gun, Japan 171 Tyrol, Austria 527 Colorado, USA 2138 Merry Widow mine, Vancouver Island, British Columbia, Canada 2448

Data courtesy of RRUFF project at University of Arizona, used with permission.

ICDD 25-0157

Forms a series with Tremolite (see here)
Forms a series with Ferro-actinolite (see here)

Tremolite-actinolite series Group > Calcium Amphibole Subgroup > w(OH, F, Cl)-dominant Amphibole Group

Dust from asbestiform varieties of actinolite can cause serious and irreversible lung disease when inhaled. Avoid creating or inhaling dust.

Kirwan, R. (1794) 16th species: actynolite. in Elements of Mineralogy, 2nd Edition, Volume 1, Elmsly (London) 167-170.

Hawthorne, F.C. (1983) The crystal chemistry of the amphiboles; Introduction. The Canadian Mineralogist: 21: 174.

Hawthorne, F.C. (1983) The crystal chemistry of the amphiboles; Classification and nomenclature. The Canadian Mineralogist: 21: 175-176.

Mandarino, J.A. (1998) The Second List of Additions and Corrections to the Glossary of Mineral Species (1995). The Amphibole Group. Mineralogical Record: 29: 169-174.

Hawthorne, F.C., Oberti, R. (2006) On the classification of amphiboles. The Canadian Mineralogist: 44: 1-21.

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