Kyanite spectra

Kyanite Visible Spectra (300 - 1500 nm)

The blue color of metamorphic kyanite comes from both the Fe²⁺ - Ti⁴⁺ and Fe²⁺- Fe³⁺ intervalence interactions. Deep blue crystals have larger amounts of the Fe²⁺ - Ti⁴⁺ intervalence interaction. The green color of kyanite from Dodoma, Tanzania comes from Fe³⁺. Both ferric iron green and a zone of blue intervanance charge transfer occurs in kyanite from Minas Gerais, Brazil. Sky blue kyanite found in diamond pipes such as the Roberts Victor Mine in South Africa contains Cr³⁺. Rare examples of Mn³⁺-containing orange kyanite are found in Loliondo, Tanzania..

Kyanite dominated by intervalence absorption

GRR 285 spectrum; from Minas Gerais, Brazil. This is the deep blue center of a 4.218 mm thick cleavage slab. The body of the sample is yellow-green (from Fe³⁺) and the typical blue streak is superimposed in the center of the crystal. The blue color is from the intervalence interactions. Sharp features near 380 and 430 nm are from from Fe³⁺ as is the broad band 1020 nm.
HVD105650 spectrum ; from Itabira, Minas Gerais, Brazil. This is the deep blue center of a 1.05 mm thick cleavage slab. The color is from the intervalence interactions. Weak features from Fe³⁺ occur at about 380 nm.
MT Yakutia: from Yakutia (now Sakha Republic), Russia. This is a blue crystal plotted as 1.0 mm thick. In the spectrum of this crystal, the band in the 800 nm region (Fe²⁺- Fe³⁺ intervalence charge transfer) is nearly as strong as the Fe²⁺ - Ti⁴⁺ band in the 620 nm region. Contributed data from Michail Taran, Kyiv, Ukraine. Data files: E\\a, E\\c.

Chromium-containing kyanite

GRR 343 spectrum; from Reitfontein Pipe, South Africa. Plotted as 1.0 mm thick. The color of this material comes from its Cr³⁺ content. Data Files: alpha; beta; gamma;
GRR 1692 spectrum; from Kenya. This is a blue, 0.735 mm thick cleavage slab. The color is from both Fe³⁺ and Cr³⁺.

Orange manganase-containing kyanite

CIT-15871 spectrum; from Nani, Loliondo, Arusha Region, Tanzania. Golden color sample 3.796 mm thick. Data Files: near gamma orientation.
GRR 544; from Mautia Hill, Kongwa, Tanganika (now in the Dodoma Region of Tanzania). An orange color sample.

Link to a collection of references to mostly color and visible spectroscopy of kyanites

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last upgraded 7-July-2022