Optical Spectra of Grandidierite, (Mg,Fe)Al₃(BO₃)(SiO₄)O₂ 

• Rossman GR, Taran Mn (2001) Spectroscopic standards for four- and fivefold-coordinated Fe²⁺ in oxygen-based minerals. American Mineralogist 86, 896–903. 
• Bupparenoo P, Maneekrajangsaeng M (2017) “Gem-Quality Grandidierite from Madagascar” The Gem and Jewelry Institute of Thailand. March 2017. 8 pages.