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(For further information on spectroscopy, see:
http://speclab.cr.usgs.gov)
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 sieved to less than 250 µm.
It probably contains enough iron to be considered a ferro-actinolite.
IMAGE_OF_SAMPLE:
NO PHOTO
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 KEYWORD |
Oxide ASCII |
Amount | Weight Percent, % |
Oxide html |
|---|---|---|---|---|
| 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, Colorado.
END_COMPOSITION_DISCUSSION.
MICROSCOPIC_EXAMINATION:
Mineral mode:
| 90 vol% | Actinolite | pop1 avg. grain size = 255µm | 25% coated with smaller actinolite grains |
| 2 vol% | Actinolite | pop2 avg. grain size = 30µm |
| 8 vol% | Biotite? | pop3 avg. grain size = 230µm | coated with small actinolite grains |
avg. grain size 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: 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 62 | 0.2-3.0µm | 200 | g.s.= 250 µm |
| LIB_SPECTRA: | splib05a r 107 | 0.2-3.0µm | 200 | g.s.= |
| LIB_SPECTRA: | splib06a r 223 | g.s.= |