Mineral Guide > Marbles

Marbles

MarblesThe origin of the name marble, like that of many another name now in common use, is somewhat obscure.

By many authorities the word is supposed to have been somehow connected with the Greek word meaning "sparkle." However this may be, a sparkling appearance is by no means universal among marbles, but is limited to those which, like the white statuary or other crystalline varieties have a granular structure, the sparkling itself being due to the reflection of light from the smooth surfaces of the constituent minerals.

As used today, the word marble is made to include any lime rock of such color and hardness as to make it desirable for ornamental, or even the higher grades of building work. Stones of precisely the same composition and origin, which are not of the desired color, are classed simply as limestones.

Accepting the definition given above, it follows, then, that with a few exceptions, to be noted later, marbles are but hardened and otherwise changed beds of marine sands and muds, containing, it may be, still recognizable fragments of the corals and mollusks of which they were originally composed.

But inasmuch as these muds were rarely of pure carbonate of lime, but were contaminated with matter from seaweeds and animal remains, or by iron compounds, so the resultant marble is not always white, but, if containing matter from plants or animals, gray, blue gray, or even black; and if containing iron, buff, pink, or red.

If the change in form of the original muds was just sufficient to produce crystallization, we may have a marble full of fossil remains which may be of a white or pink color, standing out in fine contrast with the darker ground. If, on the other hand, the change was complete, we may have a marble of small granules, pure white in color, and of a texture like loaf sugar, such as to render it suitable for statuary purposes.

It was stated before that not all our marbles were changed (metamorphosed) marine sediments. The exceptions are:

(1) the onyx marbles, which, though composed of carbonate of lime, like the last, are deposited from solution, and

(2) the so-called verdantique marbles, which are mainly altered eruptive rocks.

These last differ widely from those we have been describing, being of a prevailing green color, though often variegated with white or red. They are, in fact, not to be classed with the lime rocks at all. Their names verdantique, verte antique, and verde antique are but varying forms of the same words, indicating a green antique marble. The term antique has been applied simply because stones of this type were used by ancients, and particularly by the Romans.

The so-called onyx marbles are, as noted above, spring deposits, differing from ordinary lime deposits only in color and degree of compactness. The name has also been made to include the stalagmites and stalactites in caves, such as were used by the ancient Egyptians in the construction of alabastrons, amphorae, funeral urns, and various household utensils. The material is translucent and often beautifully clouded and veined in amber, green, yellow and red colors. Owing to its mode of origin it shows a beautiful wavy banding, or grain, like the lines of growth in the trunk of a tree when cut across the bedding. This fact, together with its translucency, has been the cause of the wrong use for it of the name onyx, which properly belongs to a banded variety of agate. Equally wrong and misleading is the name " oriental alabaster," which is commonly applied to the Egyptian variety, the true alabaster being a variety of gypsum.

The larger part of our onyx marbles come today from Mexico, though there are equally good materials of this type in Arizona and California.

The foreign supplies come in part from Algeria, and in part from Egypt. Their use is almost wholly for interior decoration, as wainscotings, etc., and for tops to small stands, bases for lamps, etc. These are by far the most expensive of any of the stones to which the name marble is properly applied.

Some of the most noted of our foreign marbles are those of Carrara, Italy, which are ancient sediments which are thought to have been changed at the time of the uplifting which formed the Apennines. They are of white and blue gray colors, sometimes beautifully veined. A beautiful mellow yellow to drab variegated variety, very close in texture and almost waxy in appearance, is found near Sienna, and is known as Sienna marble. It is a great favorite for interior decorative work, as may be seen to advantage in the vestibule of the new public library building in Boston, and the rotunda of the National Library building at Washington.

Other marbles, which at the present time are great favorites with the architects, are the so-called Numidian marbles, from Algeria. These are of a yellow, pink and red color, and often beautifully mottled. Their textures are so close that they take a surface and polish almost like enamel. Since their first hardening these beds have been shattered like so much glass into countless angular fragments, and then the whole mass, with scarcely any disturbance, once more cemented into firm rock. The result is such that when large blocks are sawn into the slabs, and the slabs then polished and spread out, the same series of veins, of angular blocks and streaks of color, may be traced from slab to slab, ever repeating themselves with only slight changes throughout the entire series.

Old Tennessee Marble picture
Sienna Marble picture
Florentine Vermont Marble picture
Alps Green Marble picture
Mexican Onyx Marble picture
African Marble picture