MINERAL RESOURCES OF THE STATE OF NEW YORK 269 

 MARBLE 



Marble, in the commercial sense, like granite, includes a variety 

 of rocks that lend themselves to building or decorative uses. Most 

 commonly, the name signifies a crystalline aggregate of calcite or 

 dolomite, as distinguished from ordinary limestones which at best 

 are of indistinctly crystalline nature. At the same time it implies 

 the feature of attractivensss by reason of color and the ability to 

 take a lustrous polish. Rocks possessing all these features are 

 marbles in the strict sense to which the name may be applied without 

 qualification. Some compact or granular limestones that lack the 

 elements of thorough crystallinity make, however, a handsome 

 appearance when polished, and such are commercially classed as 

 marbles. Fossil marbles, black marbles, and a few other kinds are 

 commonly of the noncrystalline type. Serpentine marble, or verd 

 antique, is made up for the most part of the mineral serpentine, a 

 silicate of magnesium and iron, and is therefore not related to the 

 varieties already described. Ophitic limestone, or ophicalcite, is 

 a crystalline limestone or dolomite carrying grains and nodules of 

 serpentine scattered more or less evenly through its mass. Its 

 ornamental quality lies in the speckled or mottled pattern and the 

 sharp contrast between the clear white mass and the greenish 

 serpentine inclusions. 



Marbles belonging to those various types find representation in 

 the geologic formations of the State and are quarried on a commercial 

 scale or have been so quarried in the past. 



Distribution. The true or crystalline varieties are limited in 

 occurrence to the metamorphic areas of the Adirondacks and south- 

 eastern New York. They are of early geologic age, antedating the 

 period of crustal disturbance and metamorphism which in the 

 Adirondacks was brought to a close practically before Cambrian 

 time and which in southeastern New York was completed in the 

 Paleozoic. This thoroughly crystalline character is in fact a develop- 

 ment of the strong compression accompanied by heat to which 

 they have been subjected; having been originally, no doubt, ordinary 

 granular or fossiliferous limestones similar to those so plentifully 

 represented in the undisturbed formations outside the regions. 



The crystalline limestones of the Adirondacks are most abundant 

 on the western border in Jefferson, Lewis and St Lawrence counties 

 where they occur in belts up to 4 or 5 miles wide and several times 

 as long, interfolded and more or less intermixed with sedimentary 

 gneisses, schists and quartzites. They are found in smaller and 

 more irregularly banded areas in Warren and Essex counties on the 



