Clark and others 2007 USGS Data Series 231
Spectral Library splib06a Sample Description

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

TITLE: Malachite HS254 DESCRIPT

DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: HS254

MINERAL_TYPE: Carbonate

MINERAL: Malachite

FORMULA: Cu2CO3(OH)2

FORMULA_HTML: Cu₂CO₃(OH)₂

COLLECTION_LOCALITY: Bisbee, Arizona

ORIGINAL_DONOR: Hunt and Salisbury Collection

CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

SAMPLE_DESCRIPTION:

Original spectrum published in: Hunt, G.R., J.W. Salisbury, 1971, Visible and near-infrared spectra of minerals and rocks: II. Carbonates. Modern Geology, v. 2, p. 23-30.

With the following notes: "Malachite, CuCO₃•Cu(OH)₂, like azurite is a basic carbonate of copper. More common than azurite, it is still only a minor ore of copper, occurring as a secondary mineral in the upper oxidized zone of copper deposits. This particular sample appears to be relatively pure."

"Like azurite, malachite presents an atypical carbonate ion spectrum. Apart from the broad 0.8µm band and the short wavelength fall-off below 0.52µm, due to electronic transitions in the Cu²⁺ ion, only 3 bands are present. By analogy with the spectrum of pure CuCO₃, we assign all three at 2.29, 2.37 and 2.52µm to the CO₃" radical. Some contribution to the 2.37µm band may come from OH', but no other hydroxyl bands are visible in the spectrum, a circumstance for which we have no explanation."

IMAGE_OF_SAMPLE:

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

Malachite - major component
Possibility of some Mcguinnessite can't be ruled out
Trace of undetermined phase

Konnert, Judith and Marta Flohr, 1992, unpublished data, USGS Reston, VA.

END_XRD_ANALYSIS.

COMPOSITIONAL_ANALYSIS_TYPE: None # XRF, EM(WDS), ICP(Trace), WChem
COMPOSITION_TRACE:

COMPOSITION_DISCUSSION:

None.

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

END_MICROSCOPIC_EXAMINATION.

SPECTROSCOPIC_DISCUSSION:

END_SPECTROSCOPIC_DISCUSSION.

SPECTRAL_PURITY: 1b2b3b4_ # 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 2885	0.2-3.0µm	200	g.s.=
LIB_SPECTRA:	splib05a r 4267	0.2-3.0µm	200	g.s.=
LIB_SPECTRA:	splib06a r 13289			g.s.=
LIB_SPECTRA:	splib06a r 13301			g.s.=