DOCUMENTATION_FORMAT: MINERAL

SAMPLE_ID: HS102

MINERAL_TYPE: Carbonate

MINERAL: Dolomite (Dolomite group)

FORMULA: CaMg(CO3)2

FORMULA_HTML: CaMg(CO₃)₂

COLLECTION_LOCALITY: Lee, MA

ORIGINAL_DONOR: Hunt and Salisbury Collection

CURRENT_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory

SAMPLE_DESCRIPTION:

Forms series with Ankerite and with Kutnohorite.

"This is a recrystallized dolomitic marble, which displays the carbonate absorption features at longer wavelengths than typical for calcites. Weak absoprtion band at 1.0µm is due to ferrous iron, which is shown to be present at 0.03 wt.% in the sample."

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.

END_SAMPLE_DESCRIPTION.

XRD_ANALYSIS:

Dolomite plus trace of calcite XRD done by Norma Vergo

Clark, R.N., King, T.V.V., Klejwa, M., Swayze, G.A., and Vergo, N., 1990, High spectral resolution reflectance spectroscopy of minerals: Journal of Geophysical Research, v. 95, no. 8B, p 12,653-12,680. END_XRD_ANALYSIS.

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

COMPOSITION_TRACE: None

COMPOSITION_DISCUSSION:

END_COMPOSITION_DISCUSSION.

MICROSCOPIC_EXAMINATION:

Bimodal grain size distribution:

pop 1 avg gr sz = 288µm 98 vol%
pop 2 avg gr sz = 15µm 2 vol%

avg grain size of all populations: 285µm

Pure sample, sluggish fizz with dilute HCl. Lack of a vigorous fizz suggests very little if any calcite (this HCl mixture reacts vigorously with pure calcite samples). Uniaxial negative, high relief, higher order white, all consistent with dolomite. 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 1462 0.2-3.0µm 200 g.s. = 285µm

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

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