Blue color zoning observed in some of the unusual rubies; immersed in

What are differences among sky, Swiss and London blue topaz gems? - Quora

Jonathan Muyal's research works

Geology and mineralogy of sapphire-rich metasomatites (sapphirites) deposit at the Portezuelo de Pajas Blancas, northern Chile: Genetic implications for unusual metasomatic processes in the Central Andes - ScienceDirect

Gemmology notes

A. Les gisements de rubis de la vallée d'Hunza (Pakistan). Vue

Diffusion Ruby” Proves to be Synthetic Ruby Overgrowth on Natural Corundum — AGL Research & Publications

An interesting chrysoberyl-alexandrite combination - SSEF

Minerals, Free Full-Text

Identification of heated / unheated status on ruby and sapphire2

Interesting Set of Blue “Rough” Gemstones

Cobalt-Doped Glass-Filled Sapphire • Gem Treatment

Cobalt-Doped Glass-Filled Sapphire • Gem Treatment