Bytownite

Spectrum Details

Modality

FTIR

Category

mineral

Material Type

Tectosilicate

Sample ID

HS105.1B, HS105.2B, HS105.3B, HS105.4B, HS105.6

Collection Locality

Essex County, New York

Spectral Purity

1b2_3_4_ # Bytownite HS105.1B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns SPECTRAL_PURITY: 1b2_3_4_ # Bytownite HS105.2B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns SPECTRAL_PURITY: 1b2b3b4b # Bytownite HS105.3B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns SPECTRAL_PURITY: 1b2_3_4_ # Bytownite HS105.4B # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns SPECTRAL_PURITY: 1b2_3_4_ # Bytownite HS105.6 # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns

Composition / XRD

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

Sample Description

Part of the albite-anorthite solid solution series. Grain size fractions are indicated by the extension after the sample number: .1B = IMAGE_OF_SAMPLE: NO PHOTO

XRD Analysis

40 kV - 30 mA, 6.5-9.5 keV File: labrd105.mdi References: Borg and Smith (1969); Kroll (1983); PDF2 #41-1486, 19-0926 Found: Plagioclase feldspar, probably intermediate composition Comments: Peaks are moderately sharp peaks but show poorly resolved alpha1-alpha2 components, perhaps due to some variation in composition or structural state. Line-based search-match returns 10 plagioclase feldspars in the first 10 hits; the most likely hit (and only feldspar) from profile-based search-match is #41-1481, disordered An83Ab17 (bytownite). The delta 2 theta(131)-(1-31)=1.82 degrees and corresponds to low plagioclase (or intermediate albite) structural state and composition less than 53% anorthite component (Kroll, 1983, fig. 12). Reflections diagnostic of low plagioclase composition (Kroll, 1983, p. 328-9) yield Si/Al=1.3:1 (bytownite composition). There were unindexed reflections: 8.55 Angstroms (weak) is observed in other patterns and may be instrumental in origin; 4.23 Angstroms (very weak) could be explained by a trace of K-feldspar; and 1.829 Angstroms (moderately weak) remains unexplained.

X Units

cm⁻¹

Y Units

Absorbance

Data Points

1,801