Glass Particles
A number of the outer vesicles were filled with sand when
the rock was created. As the meteorite came through the Earth's atmosphere
and the external vesicles were heated, many of
them
acted
as small crucibles, melting and shaping the sand contained within into small
little pieces of glass. These glass ingots apparently cooled before the
rock hit the ground, since they are shaped like the vesicle on their bottom
sides, yet are flat on their top sides. The melting of the sand within the
vesicles to make glass shows that the sand was placed within the vesicles first,
and then later in the history of the rock, this sand was melted, only in the
outer vesicles. This is concrete evidence of the rock's heating as it
entered Earth's atmosphere. Many of the particles contained within the
glass are not melted. The exact temperature this particle endured could
probably be determined just by finding the melting point
of the various materials that make up the little glass ingot.
The second and third pictures show the same particle, but under different lighting conditions. The last picture is closer to "true color" than the second, but the second shows some details of the little glass ingot more clearly.
