MACHINE FINISH - The generally recognized standard machine finish produced by the planers.

MALLET - Type of wood or plastic hammer, used to drive chisels.

MALPAIS - Literally, badland; refers to dark-colored rock, commonly lava, in rough terrain.

MANTEL - The structural member spanning the opening of a fireplace. Also, a shelf (usually cubic stone) which is part of the finish and above the fireplace opening.

MANUFACTURED - Dimensional stone fabricated, ready for installation.

MANUFACTURER - One who fabricates dimensional stone.

MARBLE (Architectural term) - Calcium Carbonate with other components which give it color, markings, and texture suitable as a desirable building stone.

MARBLE (Commercial term) - A crystalline rock composed predominately of one or more of the following materials

MARBLE (Scientific term) - A metamorphic (recrystallized) limestone composed predominately of crystalline grains of calcite or dolomite or both, having interlocking or mosaic texture.

MARBLE INSTITUTE OF AMERICA - An international trade association whose membership is composed of contractors, exporters, importers, manufacturers, producers, and wholesalers of dimensional stone, as well as those who supply products and services to the industry.

MASH HAMMER - A short-handled heavy hammer with two round or octagonal faces, used to drive hammer-head shaping tools.

MASON - Worker or installer of stone.

MASONRY - The practice of the mason’s craft with brick, tile, concrete masonry units and other materials. Or, the work resulting from the practice of the mason’s craft; structures built of stone, brick or other materials set as units in patterns and amenable to assembly with mortar whether or not mortar is usually used. Or, the type of construction made up of masonry units laid with mortar or grout or other accepted method of jointing.

MASONRY CEMENT - A mill-mixed cementious material to which sand and water is added to make mortar.

MASONRY UNIT - Natural or manufactured building units of fired clay or shale, concrete, stone, glass, gypsum, etc…

MASTIC - A pasty, mortar-like material composed of solvent-based organic adhesives that cures quickly by evaporation of the solvents.

MATCHING - Selecting, cutting, and placing finished stone slabs to obtain a uniform and symmetrical pattern of natural veining and color.

MATRIX - The rock in which a crystallized mineral is embedded.

MECHANIC - One skilled in installation of dimensional stone.

MEGALITH - A stone of great size.

MENSA - The top horizontal member or surface of an altar, usually of stone.

METAMORPHIC ROCK - Rock altered in appearance, density and crystalline structure, and in some cases mineral composition, by high temperature or pressure, or both. Slate is derived from shale; quartzite from quartz sandstone; and true marble from limestone.

METAMORPHISM - The change or alteration in a rock caused by exterior agencies, such as deep-seated heat and pressure, or intrusion of rock materials.

METER - A unit of linear measure in the metric system; equivalent to 39.37 inches.

MICA - Any group of mineral silicates in a multi-layered form; characterized by cleaving which permits splitting into thin sheets.

MICROCRYSTALLINE LIMESTONE - A limestone that consists largely or wholly of crystals that are so small as to be recognizable only under magnification.

MILLING - Processing of quarry blocks through sawing, planing, turning, and cutting.

MITER - The junction of two units at an angle, of which the junction line usually bisects on a 45’ angle.

MOCK-UP - A large or full size stone sample panel installed to show full range of color, shading and texture.

MODULAR-MULTIPLE CUT PATTERN CUT - This refers to standard patterns used throughout the stone industry. These patterns are usually based on multiples of 3" or 6", stone that is multiple cut or pattern cut is pre-cut to allow for ¼" or ½" joints or beds.

MODULUS OF RUPTURE - The stress at which a specimen of stone breaks in the testing.

MOH’S SCALE - A gauge of hardness among minerals. Not to be confused with hardness as determined by ASTM C241 test.

MOLD - Formed template. Sometimes spelled in the trade as "mould."

MOLDINGS - Decorative stone deviating from a plane surface by projections, curved profiles, recesses, or any combination thereof.

MONO SAW - Similar to gang saw, except it has only one blade for cutting large stone units.

MONOLITHIC - Shaped from a single block of stone, as a monolithic column, in contrast with a stacked column consisting of superimposed stone drums. Also, a bed of portland cement cast over a concrete slab without an isolation membrane.

MORTAR - A plastic mixture of cement , water, and fine aggregates which combine together through a chemical process of crystallization to form a hardened solid that bonds building units together.

MORTAR - FAT MORTAR - Mortar containing a high percentage of cementitous components. It’s a sticky mortar that adheres to a trowel.

MORTAR - LEAN MORTAR - Mortar that is deficient in cementitious components. It is usually harsh and difficult to spread.

MORTAR - NONSTAINING MORTAR - A mortar with a low free-alkali content to avoid efflorescent or staining by adjacent stones migration of soluble materials.

MORTAR BED - A troweled layer of mortar, in a plastic state, in which building units will be set.

MOSAIC - A veneering which is generally irregular with no definite pattern. Nearly all the stone used in a mosaic pattern is irregular in shape.

MULLION - Vertical division member between windows or doors

MULTIPLE PATTERN - Stone cut in rectangular multiples of a certain dimension. Usually cut to allow for standard ¼" or standard ½" joint.

MULTIPLE-RISE ASHLAR - Stone, usually splitface, which is cut in various rises which will "course out" (level with) each other when used in proper combination with standard-width mortar joints.

MUSCOVITE - A white, aluminum-rich mica found in granite.

NATIONAL ASSOCIATION OF MARBLE PRODUCERS - The National trade Association of the American Marble Industry whose membership is composed of marble producers (quarries) in the United States, its territories and Canada.

NATURAL BED - The setting of the stone on the same plane as it was formed in the ground. This generally applies to all stratified materials.

NATURAL CEMENT - Lime with high clay content.

NATURAL CLEFT - This generally pertains to stones which are formed in layers in the ground. When such stones are elevated or separated along a natural seam, the remaining surface is referred to a natural cleft surface.

NATURAL STONE - Although technical a redundancy, as a stone its occurrence by term, the term is used to distinguish true stone from imitation materials.

NEAT CEMENT - A pure cement uncut by a sand admixture.

NET CROSS-SECTIONAL AREA - The net cross-sectional area of a masonry unit is the gross cross-sectional area minus the area of the cores or cells. For brick units cored less than 25% the net area is equal to the gross area. Or, the area of masonry units, grout, and mortar crossed by the plane under consideration based on out-to-out dimensions.

NET CROSS-SECTIONAL AREA - See cross-sectional area.

NICKED BIT FINISH - Obtained by planing the stone with a planer tool in which irregular nicks have been made in the cutting edge.

NOMINAL DIMENSION - A dimension greater than a specified masonry dimension by the thickness of a mortar joint.

NON-FERROUS - Not containing iron material.

NON-STAINING MORTAR - Mortar composed of materials which individually or collectively do not contain material that will stain and usually have a very low alkali content.

NONCOMBUSTIBLE - Any material that will neither ignite nor actively support combustion in air at a temperature of 1.200’F when exposed to fire.

NONCORRODING - Resistant to harmful oxidation or other corrosive actions because of its composition (i.e. stainless steel, bronze, copper).

NOSING - The rounded front edge of a stair tread.

NOTCHED TROWEL - Trowel with a serrated or notched edge used for spreading mortar or adhesive in ridges of a specific thickness.

O.C. - On centers, an abbreviation frequently used in dimensioning shop drawings, designating dimensions from the center of one member to the center of the next.

OBSIDIAN - A glassy phase of lava, usually black.

OFFSET - A course or unit that is set in from the course directly under it, the opposite of a projection.

OGEE - A stone molding with a reverse curved edge, concave above, convex below.

ONE-MAN BOULDERS - Rough stone under 150 pounds.

ONYX - A variety of quartz in crystalline form of calcium carbonate. It is characterized by a structure of parallel brands each differing in color or in the degree of translucency.

ONYX MARBLE - A crystalline from, commonly microcrystalline, of calcium carbonate deposited usually from cold water solutions. It is generally translucent and shows characteristic layering. Commercially, onyx is considered a marble because it can be polished.

OOLITIC LIMESTONE - Rock consisting mainly of calcite, made up of largely oolites or granular particles (generally tiny fossils or fossil fragments) that have calcium coatings. A calcite-cemented calcareous stone formed of shells and shell fragments, practically non-crystalline in character it is found in massive deposits located almost entirely in Lawrence, Monroe, and Owen counties in Indiana, also in Alabama, Kansas, and Texas. This limestone is characteristically a freestone, without cleavage planes, possessing a remarkable uniformity of composition, texture and structure. It also possesses a high internal elasticity, adapting itself without damage to extreme temperature changes.

OPALIZED - The introduction into a rock of siliceous material in the form of opal, a hydrous silicate.

OPEN-FACED QUARRY - Open, fairly level quarry at or near ground level.

ORGANIC - Designation of any chemical compound containing carbon (some of the simple compounds of carbon, such as carbon dioxide, are frequently classified as inorganic compounds). To date, nearly one million organic compounds have been synthesized or isolated. Many occur in nature; others are produced by chemical synthesis.

OUT-CROP - Rock protruding above or at ground level.

OUT-OF WIND - Generally refers to veneer stone. To be out of wind is to have the arris of the stone not in parallel or perpendicular lines; stone which is out of wind has an irregular or rustic appearance.

OVER BURDEN - Waste stone, earth or other quarry material covering useful stone.