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: "Porridge" beads are likely porhyritic rock in the granite-diorite realm
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I ran a 32x12 oval bead that had what I've been calling a "porridge" look through an ultrasonic cleaner, and that removed enough dust to reveal the porphyritic feldspar crystals dancing around against the dark matrix. Both beads in the picture on the right now sparkle in the sun from the tiny crystals in their composition. So, the "speckled" and "porridge" beads seem likely to have been made from the same igneous rock, and are not gneiss (a metamorphic rock). Where that rock was quarried remains a mystery. The bead on the left in the second picture is some sort of granite, possibly due to some pinkish potassium feldspar (K-spar) in its composition (or maybe just red dirt concretions or stains that the ultrasonic did not remove). The ultrasonic removed the coating of old oil or grease that was obscuring the glitter. The general shape of this bead and its large, worn holes seems to put it into the category of old granite beads that were imitated by glass, as described in the two articles cited above in this thread.
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