The brilliant colors of rubies and emeralds come from the presence of very small amounts of chromium. The chromium replaces about 1% of the aluminum in the corundum or beryl crystal when a ruby or ...
available credits for a new roof do not differentiate between a new asphalt shingle roof and a new metal roof, but it’s likely to be among the updates, Yaworksy said. “Roofs are probably the ...
With a theory developed by physicists in the 1920s called crystal field theory, scientists can explain why rubies and emeralds have the colors they do. Crystal field theory makes predictions about how ...