PROSPERITY SITE

Plane polarized light is just visible light under the microscope. Crossed (X) polarized light allows you to see mineral characteristics such as twinning in the feldspar and alteration. At 2.5X magnification, the distance across the slide is 4.8 mm and at 10 X magnification it is about 1.2 mm.

P1: This sherd is composed of very fine to fine grain plagioclase and quartz with much lesser amounts of mica and opaque mineral grains. Mineral grains are angular to sub-angular. Firing conditions were oxidizing and no evidence of slip or glaze is found.

2.5X magnification. Plane polarized light.

2.5X magnification. Crossed polarized light. Majority of grains are quartz (monocrystalline with a few polycrystalline grains with sutured boundaries) and feldspar.

10X magnification. Cross polarized light. Note polysynthetically twinned feldspar (lower right), monocrystalline and fractured quartz grains and the subangular to subrounded shape. The high relief grain (high interference colours - 2nd order) is probably tourmaline.

P2: This sherd is similar in grain size, grain texture and mineralogy to P1, however, a few polycrystalline rock fragments composed of quartz + feldspar were observed. Blocky shaped, opaque mineral grains (< 1%) were found. Firing conditions were oxidizing with a slightly reduced core region and no evidence of slip or glaze, or coil break, was found.