IN FOCUS

An interesting tuft of light blue needles was recently observed in a polished modified cube of rock crystal quartz (figure 1). The needles nucleated on a nearly invisible quartz crystal with the…

Recently the authors examined a 4.8 cm tall pale blue sapphire crystal (figure 1) that featured numerous purple spinel crystals up to 8 mm in size on the surface (figure 2), a…

Numerous gem materials have been designated “trapiche” in the trade and in various publications. They generally describe a pattern consisting of a fixed non-transparent star in a transparent matrix, with the arms…

Recently examined in the Carlsbad laboratory was a 26.72 ct transparent violet modified cushion mixed-cut stone (figure 1). Standard gemological testing revealed a refractive index of 1.583–1.592 and a specific gravity of…

A white, non-nacreous baroque pearl weighing 15.53 ct and measuring 19.54 × 13.26 × 11.57 mm (figure 1) was recently submitted to GIA’s Carlsbad laboratory for examination. Information from previously observed non-nacreous…