Context: "Scarab, only one half preserved, cracks in the glaze on the back, side and base, burnt, partially linear, partially hollowed-out engraving, hatching, enstatite, white with yellow glaze and remains of dark green glaze in the engraving" (from object description of U6510, p. 286: Seals and Seal Impressions from Excavation Seasons 1984-2000. Eggler, herr, Root. Chapter 13 in MPP Vol. 5.)
Enstatite is the magnesium endmember of the pyroxene silicate mineral series enstatite (MgSiO3) - ferrosilite (FeSiO3). The magnesium rich members of the solid solution series are common rock-forming minerals found in igneous and metamorphic rocks. The intermediate composition, (Mg,Fe)SiO3, has historically been known as hypersthene, although this name has been formally abandoned and replaced by orthopyroxene. When determined petrographically or chemically the composition is given as relative proportions of enstatite (En) and ferrosilite (Fs) (e.g., En80Fs20). (Wikipedia, Enstatite)
I'm not sure what any of that means. I'm not a geologist. But Talea is. So for her viewing pleasure, I introduce, enstatite. Lots of scarabs from Tall al-'Umayri, at Jordan, were made of enstatite.
Um, were the minerals on this supposed to have formed in the kiln, in a volcanic event, or in an earthquake? Yeah, that went right over my head. Partly I'm confused because the deposits are supposed to form in igneous OR metamorphic situations (in presence of heat or pressure, right?) but those are kind of different...and kind of extreme.
ReplyDeleteCould be kiln based then, like faience? Made in a mold? Not sure. The term confused me and I've spent time looking it up but no one discusses what it is in relation to scarabs. :) Glad you helped me realize though that it's undergoing treatment of some kind. Geology. Hmpf.
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