Name: Magnetite Fe+2Fe2+3O4
Type: Mineral
Class: Oxide
Subclass: None
Particle Size: Fine
Sample No.: magnet_1
Owner: JHU
Wavelength Range: TIR
Origin: Santa Barbara, Minas Gerais, Brazil via the Smithsonian(sample no. NMNH 114111)
Collection Date: N/A
Description: The sample was composed of two large (3 cm x 3 cm x 2 cm) fragments of a single crystal, weighing 26.7 g.  The crystal fragments were dark gray in color, with good crystal faces, all of which had a red-brown, earthy material adhering in places.  These coatings were removed by ultrasonic cleaning. Particle size was Less than 2 micrometers.(Spinel Group) Original ASTER Spectral Library name was jhu.nicolet.mineral.oxide.none.powder.magnet1.spectrum.txt
Mineral:  Magnetite Fe+2Fe2+3O4

Sample No.: magnet.1

Under the microscope, the sample appeared contaminated by <1% of 
some unidentified, clear to reddish brown material(s).

XRD Analysis:  Magnetite with minor kaolinitic contamination and, 
perhaps, some chlorite (?).  (The infrared spectrum is essentially that 
of pure magnetite and the microprobe analysis also indicates rather 
pure magnetite, so the mineral was retained in the library.)

Chemistry:  Microprobe analysis indicates pure magnetite.  Average 
of eight analyses:

SiO2 	0.07
Al2O3	0.03
FeO	93.31
MgO	0.13
CaO	0.08
K2O	0.02
Na2O	0.03
TiO2	0.29
	_____
Total	*93.96
	*Low because no distinction made between ferrous and ferric 
iron in analysis.
