Feature Gems & Gemology, Winter 1999, Volume 35, No. 4

Diopside Needles as Inclusions in Demantoid Garnet from Russia: A Raman Microspectrometric Study

Straight, acicular, colorless solid inclusions in demantoid garnet from the Ural Mountains of Russia were investigated by laser Raman microspectrometry. These “needles,” which occur in association with “horsetail” inclusions (curved, fibrous chrysotile), were identified as diopside. This study also demonstrated that Raman analysis is a highly sensitive method for distinguishing even between isomorphous mineral inclusions in gems, that is, minerals with similar crystal structures but different chemical compositions