Sea Blue Chalcedony

Sea Blue Chalcedony is produced by dyeing natural chalcedony, which is porous enough that light-colored material can be dyed almost any color. The sources read do not state where the starting chalcedony is mined. Naturally blue chalcedony also exists (for example from Namibia, California and Nevada), but it is usually a paler, grayish blue whose color comes from light scattering.

In 2020 GIA's Tokyo laboratory examined beads bought in Tokyo as "sea-blue chalcedony". RI (1.53–1.54), SG (2.48–2.65), curved banding and Raman spectra identified them as chalcedony; EDXRF and UV-Vis spectra pointed to copper as the coloring element, no polymer was found, and whitish zones following surface fractures showed they were quench-crackled dyed chalcedony. Such beads can resemble Larimar (blue pectolite, RI about 1.60, SG about 2.80) but are easily separated by RI and SG. In general, dyed blue chalcedony may appear pink under the Chelsea filter.

Dyeing of chalcedony is described as usually stable. Like other chalcedony it is tough and can be cleaned with mild detergent, warm water and a soft brush; the dye treatment should be disclosed to buyers.

JCK reported in February 2002 that Maxam Magnata, a Tucson supplier known for natural and titanium- or platinum-coated drusy, would feature color-enhanced Sea Blue Chalcedony at that month's Tucson shows; according to Magnata it was the first time chalcedony had been permanently colored this shade of blue, with prices expected at $1.50 to $5 per carat. In an April 2003 Colored Stone article, Magnata said about 80 percent of his chalcedony sales were enhanced material and that the new dyed Sea Blue Chalcedony had been very popular.