DOCUMENTATION_FORMAT: MINERAL
SAMPLE_ID: HS297.1B, HS297.2B, HS297.3B, HS297.4B
MINERAL_TYPE: Phyllosilicate
MINERAL: Chrysocolla
FORMULA: (Cu,Al)2H2Si2O5(OH)4*nH2O
FORMULA_HTML: (Cu,Al)2H2Si2O5(OH)4•nH2O
COLLECTION_LOCALITY: Miami, AZ
ORIGINAL_DONOR: Hunt and Salisbury Collection
CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
SAMPLE_DESCRIPTION:
Chrysocolla is a hydrogel or gelatinous precipitate.
"C-5 Chrysocolla 297B--Miami, Ariz. CuSi03nH20: Chrysocolla is a secondary mineral occurring in the oxidized zone of copper veins. The spectrum is dominated by the intense Cu2+ absorption near 0.75 µ, which together with the fall off in reflectivity to the blue, produces a reflectivity maximum near 0.5 µ and the blue green color of the mineral. Constitutional water produces the very intense 1.42 µ and 1.92 µ bands as well as the 2.23 µ feature."
Hunt, G.R., J.W. Salisbury, and C.J. Lenhoff, 1973, Visible and near-infrared spectra of minerals and rocks: VI. Additional silicates. Modern Geology, v. 4, p. 85-106.
Grain size fractions are indicated by the extension after the sample number:
.1B = <5 µm
.2B = <74 µm
.3B = 74-250 µm
.4B = 250-1200 µm
END_SAMPLE_DESCRIPTION.
XRD_ANALYSIS:
Quartz - significant component
Chrysocolla - possible component
Note: Except for quartz this sample is amorphous. Chrysocolla is
amorphous, therefore XRD is not a definitive test for chrysocolla.
Konnert, Judith and Marta Flohr, 1992, unpublished data, USGS Reston, VA.
END_XRD_ANALYSIS.
COMPOSITIONAL_ANALYSIS_TYPE: None # XRF, EPMA, ICP(Trace), WChem
COMPOSITION_TRACE: None
COMPOSITION_DISCUSSION:
None
END_COMPOSITION_DISCUSSION.
MICROSCOPIC_EXAMINATION:
mode:
90 vol% chrysocolla
10 vol% cryptocrystalline quartz
Light blue color, conchoidal fracture, fine fibrous crystal habit so optic sign cannot be determined (actually chrysocolla is amorphous so it would not have an optic sign). Soft. All consistent with chrysocolla. G. Swayze.
END_MICROSCOPIC_EXAMINATION.
SPECTROSCOPIC_DISCUSSION:
END_SPECTROSCOPIC_DISCUSSION.
SPECTRAL_PURITY: 1b2_3_4_ # Chrysocolla HS297.1B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1b2_3_4_ # Chrysocolla HS297.2B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1b2b3c4b # Chrysocolla HS297.3B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns
SPECTRAL_PURITY: 1b2_3_4_ # Chrysocolla HS297.4B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns