Presently, a large fraction of contemporary cobalt flame fusion sapphire growth exhibits variegated coloration, characterized by intermittent regions of green and blue hue. On rare occasions, an entire boule achieves homogenous saturation in a vivid blue tone, yielding a distinct cerulean gemstone when subsequently faceted. This chromaticity markedly deviates from the conventional blue imparted by titanium and iron. These gemstones exhibit a subtle red fluorescence, discernible in outdoor sunlight conditions.

Approximately 2-4% of cobalt flame fusion sapphire production in Thailand comprises this specific blue variant. Our current inventory of this particular material is characterized by limited availability.