This poem came from the June 5, 2012 Poetry Fishbowl. It was inspired by a prompt from catsittingstill. It has been sponsored by Anthony & Shirley Barrette. Read about diamond and quartz, sapphire and ruby.
Diamond is an allotrope of carbon,
resistant to impurities
except for traces of boron or nitrogen,
and therefore usually clear.
Quartz is made of silicon–oxygen tetrahedra
which invite the inclusion of other minerals:
iron for the violet of amethyst,
titanium or manganese for rose.
Diamond and quartz
may look similar when clear,
yet their crystal matrix
and their contents diverge.
Sapphire consists of aluminum oxide
tinted with traces of
iron, titanium, copper, or magnesium
typically yielding shades of blue.
Ruby consists of aluminum oxide
tinted with traces of chromium
creating red hues.
Sapphire and ruby
look nothing alike,
yet both of them are
types of corundum.
It is the structure,
and not the color,
that defines true nature.