TITLE: Actinolite NMNH80714 DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: NMNH80714

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: Cumberland, Rhode Island

ORIGINAL_DONOR: National Museum of Natural History

CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

SAMPLE_DESCRIPTION:

Forms series with Tremolite and Ferro-actinolite.

Sample was seived to ~<250µm.
It probably contains enough iron to be considered a ferro-actinolite.

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

40 kV - 30 mA, 6.5-9.5 keV
File: act80714.mdi (smear mount on quartz plate)
References: JC-PDS #41-1366, 44-1402, 45-1371
Found: Monoclinic amphibole, probably actinolite

Comment: Sharp amphibole peaks with clearly resolved alpha1-alpha2 components but slight peak broadening (compared with WAR-404) suggest excellent crystallinity and little compositional heterogeneity. The pattern similar to referenced JCPDS patterns. Subsequent search-match based on eight strongest lines returned 16 amphiboles among the 20 most-likely hits; profile based match returned one amphibole among five hits. In each case, the most likely hit was actinolite, #41-1366.

END_XRD_ANALYSIS.

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


COMPOSITION: SiO2 54.28 wt% SiO2
COMPOSITION: TiO2 0.02 wt% TiO2
COMPOSITION: Al2O3 2.81 wt% Al2O3
COMPOSITION: Cr2O3 0.00 wt% Cr2O3
COMPOSITION: FeO 8.60 wt% FeO
COMPOSITION: MnO 0.59 wt% MnO
COMPOSITION: MgO 18.53 wt% MgO
COMPOSITION: CaO 13.04 wt% CaO
COMPOSITION: Na2O 0.74 wt% Na2O
COMPOSITION: Total 98.61 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.

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

Mineral mode:

90 vol% Actinolite pop1 av gr sz = 255µm
25% coated with smaller actinolite grains
2 vol% Actinolite pop2 av gr sz = 30µm
8 vol% Biotite? pop3 av gr sz = 230µm
coated with small actinolite grains

av gr sz of populations = 250µm

Pure sample of prismatic green-blue fibers. Slight pleochroism, biaxial (-), two good cleavages, high birefringence, inclined extinction with angle = 12 degrees. All this is consistent with actinolite. G. Swayze

END_MICROSCOPIC_EXAMINATION.

SPECTROSCOPIC_DISCUSSION:

END_SPECTROSCOPIC_DISCUSSION.

SPECTRAL_PURITY: 1_2_3_4_

LIB_SPECTRA_HED: where Wave Range Av_Rs_Pwr Comment

LIB_SPECTRA: splib04a r 62 0.2-3.0µm 200 g.s.= 250 µm

LIB_SPECTRA: splib05a r ____ 0.2-3.0µm 200 g.s.=

LIB_SPECTRA: splib06a r ____ 1.5-25µm 250 g.s.=