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Showing posts from February, 2019

Queen's Prize 2019: Refining Ultramarine

Note: This entry won the Judge's Choice vote. Before we get to the doc, there were two sheets full of color samples I prepared from the pigment samples that I had sitting out on the table during the display, but did not include in the written documentation. Scans of both of them are below. Background Ultramarine pigment is derived from the mineral lapis lazuli. The blue color in the stone is produced by lazurite, and it essentially always has inclusions of calcite, pyrite, and other trace minerals. The best specimens are a deep blue with minimal amounts of white and silver inclusions from the calcite and pyrite respectively, while less valuable samples will have a lighter blue and significant white streaking throughout. Unless treated, only the best pieces of lapis lazuli can make a passable pigment. Lesser quality stones will only produce a dull bluish-grey color. Although lapis lazuli has a vast history of being used as a decorative stone, there is no evidenc