Herderite-Hydroxylherderite - UV-Vis spectra Herderite Index IR-Reflectance Photoluminescence UV-Vis-NIR Purple hydroxylherderite – 1.57 ct – Virgem da Lapa, Minas Gerais, Brazil Purple hydroxylherderite – 1.57 ct – Virgem da Lapa, Minas Gerais, Brazil