DOCUMENTATION_FORMAT: MINERAL
SAMPLE_ID: GDS155
MINERAL_TYPE: Borate
MINERAL: Howlite
FORMULA: Ca2B5SiO9(OH)5
FORMULA_HTML: Ca2B5SiO9(OH)5
COLLECTION_LOCALITY: Barstow, California
ORIGINAL_DONOR: Jim Piper
CURRENT_SAMPLE_LOCATION: USGS USGS Denver Spectroscopy Laboratory
ULTIMATE_SAMPLE_LOCATION: USGS Denver Spectroscopy Laboratory
SAMPLE_DESCRIPTION:
Howlite occurs as porcelaneous nodules in shale or, less commonly, silty sandstone, and as massive veins ranging from 2 to 30cm in thickness. - from Borates: Econ. Geol. & Prod., Barker and Lefond, eds. Proc. of Soc of Mining Eng, Oct 1984, Denver, p. 181.
Note howlite is very unusual in that it is the only mineral we know of with SiO9.
END_SAMPLE_DESCRIPTION.
XRD_ANALYSIS:
40 kV - 30 mA
Reference: JCPDS #35-630
Found: Howelite
Quartz sought but not found
Comment: Extraordinarily clear pattern, sharp peaks, excellent
crystallinity.
J.S. Huebner and J. Pickrell, unpublished data, written communication, USGS, Reston, VA (1993)
END_XRD_ANALYSIS.
COMPOSITIONAL_ANALYSIS_TYPE: None # XRF, EPMA, ICP(Trace), WChem
COMPOSITION_TRACE: None
COMPOSITION_DISCUSSION:
None
END_COMPOSITION_DISCUSSION.
MICROSCOPIC_EXAMINATION:
END_MICROSCOPIC_EXAMINATION.
SPECTROSCOPIC_DISCUSSION:
END_SPECTROSCOPIC_DISCUSSION.
SPECTRAL_PURITY: 1a2a3a4u # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns