Marble, in a scientific sense, is a metamorphic rock and does not occur
as such in Missouri. However, marble has been used as a name in
commercial trade to refer to a crystalline, fairly pure limestone, which
possesses most of the useful qualities of true marble. In that sense the
“marbles” quarried near Ozora and Carthage, Missouri, are very excellent
stone. No doubt some recrystallization has occurred in connection with
the faulting in the Ozora region, and this may be interpreted as mild
metamorphism. The Carthage “marble” is quarried from beds of limestone
well developed for structural purposes. These “marbles” effervesce in
acid, of course, just as described for limestone.
In this connection it is interesting to note that the polish on
limestone or marble is not durable where exposed to the weather in the
same sense as is the polish on granite. Because limestone and marble are
softer than granite they may be cut and polished at lower cost, but
because of their ease of attack by acid, water, and abrasion they soon
become dull when used as an exterior stone. For interior decoration they
are excellent, of course. Granite contains hard minerals which happen
not to be attacked appreciably by dilute acids, and therefore it retains
a polish for a long time even where exposed to the weather.