Stealing signs is not always against the rules. Major League baseball's prohibition pertains to stealing signs via electronic means only. Attempts by a team to steal signs during the game simply by observing or by other allowable means are permitted, but obviously risky and unpopular.
The metamorphic rock we selected was marble, which is formed from limestone and contains dolomite and calcite as the two main sediments. Great question! Unfortunately, I can't give an easy answer to this one. Before we continue, let's agree on some basics: calcium is an element, calcite and dolomite are minerals, and limestone is a sedimentary rock which can turn into the metamorphic rock called marble if the right conditions occur.
Calcite is the only common non-silicate rock forming mineral, being instead calcium carbonate. It has two refractive indices causing a significant double refraction effect - when a clear calcite crystal is placed on an image, a double image is observed; See the sample below. Calcite will fizz when dilute hydrochloric acid is placed on it. It may be fluorescent, phosphorescent, thermoluminescent and triboluminescent (see fluorite for definitions of these properties). Calcite is one of the most ubiquitous minerals, being an important rock forming mineral in sedimentary environments. It is an essential component of limestones, and occurs in other sedimentary rocks. It also occurs in metamorphic and igneous rocks, and is common in hydrothermal environments. Calcite is a common vein filling mineral in many rock types.