Gahnite - PL spectra Gahnite Index IR-Reflectance Photoluminescence UV-Vis-NIR Blue: Blue gahnite – 2.02 ct crystal – Kagoro Hills, Kaduna State, Nigeria Green: Dark-green gahnite – 0.24 ct crystal – Pico Das Almas River, Paramirim Das Crioulas, Erico Cardoso, Bahia, Brazil Blue gahnite – 2.02 ct crystal – Kagoro Hills, Kaduna State, Nigeria 512 and 737 nm: Mn2+640, 647 and 650 nm: Co2+ Dark-green gahnite – 0.24 ct crystal – Pico Das Almas River, Paramirim Das Crioulas, Erico Cardoso, Bahia, Brazil 512 nm: Mn2+655 nm: Co2+650-750 nm: Cr3+
512 and 737 nm: Mn2+
512 nm: Mn2+