Coquimbite

Spectrum Details

Modality

NIR

Category

mineral

Material Type

Sulfate

Sample ID

GDS22

Collection Locality

MIT Collection (Harvard Dana Collection)

Spectral Purity

1c2_3_4_ # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns

Composition / XRD

None # XRF, EPMA, ICP(Trace), WChem

Sample Description

Dimorphous with Paracoquimbite. IMAGE_OF_SAMPLE:

XRD Analysis

40 kV - 30 mA, 7.3-9.5 keV File: coqum22_mdi, *.out (smear mount on quartz plate) References: JCPDS #6-40, 27-254 Found: Coquimbite and subequal paracoquimbite Comment: Very sharp reflections, many peaks slightly asymmetric due to imperfect overlap of reflections. Suggest that these phases are well crystallized and compositionally homogeneous. Weak unindexed reflections are present but, because we find virtually all of the reflections listed on the JCPDS cards, we suspect that the unindexed reflections are coquimbite and paracoquimbite reflections that were not recorded by the JCPDS. J.S. Huebner, J. Pickrell, and T. Schaefer, 1994, written communication.

X Units

cm⁻¹

Y Units

Absorbance

Data Points

2,126