The Indiana Limestone Institute classifies Indiana Limestone into two colors and four grades based on granular texture and other natural characteristics. When specifying Indiana Limestone it is necessary to identify both the color and grade required as well as the surface finish to be applied to the stone.
1. Buff — varies from a light creamy shade to a brownish buff.
2. Gray — varies from a light silvery gray to shades of bluish gray.
The Indiana Limestone Institute classifications are based on the degree of fineness of the grain particles and other natural characteristics which make up the stone. The structural soundness of each of the grades is essentially identical.
As a natural product, Indiana Limestone contains at least a few distinguishable calcite streaks or spots, fossils or shelly formations, pit holes, reedy formations, open texture streaks, honeycomb formations, iron spots, travertine-like formations and grain formation changes. However, through the years, one of the pleasing features of Indiana Limestone which has made it adaptable to the various architectural styles is that, as these do not exist in large, noticeable concentrations from stone to stone, one piece looks very similar to another with no discernable pattern of these natural characteristics. For this reason, Indiana Limestone does not lend itself to pattern blending as do stones which have characteristics such as specifically pronounced veining which exists from stone to stone.
1. Select - Fine to average-grained stone having a controlled minimum of the above characteristics.
2. Standard - Fine to moderately large-grained stone permitting an average amount of the above characteristics.
3. Rustic - Fine to very coarse-grained stone permitting an above-average amount of the above characteristics.
4. Variegated - An unselected mixture of grades 1 through 3 permitting both the buff and gray colors.