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Clark et. al. 2003 USGS Open File Report 03-395
Spectral Library splib05a Sample Description

(For further information on spectrsocopy, see: http://speclab.cr.usgs.gov)

TITLE: Actinolite HS22 DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: HS22

MINERAL_TYPE: Inosilicate

MINERAL: Actinolite (Amphibole group)

FORMULA: Ca2(Mg,Fe+2)5Si8O22(OH)2

FORMULA_HTML: Ca2(Mg,Fe+2)5Si8O22(OH)2

COLLECTION_LOCALITY: Chester, VT.

ORIGINAL_DONOR: Hunt and Salibury Collection

CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

SAMPLE_DESCRIPTION:

Forms a series with Tremolite and Ferro-actinolite.

Original spectrum published in:

Hunt, G.R., J.W. Salisbury, 1970, Visible and near-infrared spectra of minerals and rocks: I. Silicate minerals. Modern Geology, vol. 1, pp283-300.

With the note: "The flattening of the spectral curve of the finest size range near 2 µm, which produces a cross-over of the spectra, is apparently due to a very slight contamination of the sample by opaque inclusions of pyrite (?)."

A spectrum of this sample is also published in:

Clark, R.N., T.V.V. King, M. Klejwa, G. Swayze, and N. Vergo, 1990, High spectral resolution reflectance spectroscopy of minerals: J. Geophys Res., v. 95, 12653-12680.

Who noted that the sample is spectrally pure. The sample measured was HS22.3B which was dry sieved to the grain size interval 74-250 µm.

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

40 kV - 30 mA, 7.3-9.5 keV
File: acHS22.out, *_mdi (smear mount on quartz plate)
References: Huebner's reference patterns
Found: Clinoamphibole, chlorite, trace possible talc

Comment: Excellent amphibole pattern closely matches that of a natural tremolite-actinolite. Insufficient number of chlorite reflections to determine polytype. Weak reflection at 9.2 angstroms could be the strong basal reflection of talc, which commonly occurs with tremolite-actinolite.

J.S. Huebner, J. Pickrell, T. Schaefer, written communication 1994.

END_XRD_ANALYSIS.

COMPOSITIONAL_ANALYSIS_TYPE: EM(WDS) # XRF, EM(WDS), ICP(Trace), WChem


COMPOSITION
KEYWORD
Oxide
ASCII
Amount Weight
Percent, %
Oxide
html
COMPOSITION: SiO2 54.53 wt% SiO2
COMPOSITION: TiO2 0.04 wt% TiO2
COMPOSITION: Al2O3 1.64 wt% Al2O3
COMPOSITION: Cr2O3 0.27 wt% Cr2O3
COMPOSITION: FeO 5.46 wt% FeO
COMPOSITION: MnO 0.21 wt% MnO
COMPOSITION: MgO 21.69 wt% MgO
COMPOSITION: CaO 12.01 wt% CaO
COMPOSITION: Na2O 0.41 wt% Na2O
COMPOSITION: K2O 0.03 wt% K2O
COMPOSITION: Total 96.28 wt%
COMPOSITION: O=Cl,F,S wt% #correction for Cl, F, S
COMPOSITION: New Total wt%

COMPOSITION_TRACE: None

COMPOSITION_DISCUSSION:

EM analysis by Gregg A. Swayze at USGS Branch of Geophysics, Denver, indicates stoichiometric actinolite.

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

Optical examination give the following mineral mode:

91.5 vol% actinolite
8.0 vol% wh. mica or calcite
0.5 vol% opaque inclusions

avg. grain size = 290µm

Mostly pure, highly fractured green actinolite grains (occasionally some with opaque inclusions). Platy translucent mica? grains intermixed with actinolite. Continuous grain size distribution with little coating of larger grains by smaller grains. G. Swayze

END_MICROSCOPIC_EXAMINATION.

SPECTROSCOPIC_DISCUSSION:

END_SPECTROSCOPIC_DISCUSSION.

SPECTRAL_PURITY: 1b2_3_4_ # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns

LIB_SPECTRA_HED: where Wave Range Av_Rs_Pwr Comment
LIB_SPECTRA: splib04a r 40 0.2-3.0µm 200 g.s.= 290µm
LIB_SPECTRA: splib05a r 80 0.2-3.0µm 200 g.s.=


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