The Tokyo laboratory recently received a 3.02 ct red pear-shaped mixed cut measuring 10.93 × 7.04 × 5.03 mm (figure 1). Standard gemological testing yielded a refractive index of 1.765–1.773; a hydrostatic specific gravity of 4.00; absorption lines at 693, 476, and 468 nm; and a broad absorption band between 500 nm and…
Author: Gems Expertise
Agate Inclusion in Quartz from Brazil
Agates are undoubtedly one of the most common precious stones from Brazil. They come from basalts in the state of Rio Grande do Sul, on the border with Uruguay. This region is probably also the source of several unusual faceted quartz samples, purchased by the author in Brazil in 2019. These stones are…
Yellow Fluid Inclusions in Transparent Sodalite
Microscopic observation revealed greenish yellow two-phase fluid inclusions reminiscent of petroleum in quartz (figure 2). Unlike petroleum in quartz, the fluid inclusions were inert to long-wave UV light. Raman spectra of the gas bubble and surrounding liquid were matched to gaseous hydrogen sulfide and hydrogen sulfide in solution, respectively. Methane-related peaks were also…