Category Definitions:

Aggregate: broad category of coarse particulate material used in construction, including sand, gravel, crushed stone, slag, and recycled concrete.

Ashlar: Cut, squared building stone finely dressed on all sides adjacent to other stones. Requires only very thin mortar joints.

Ashlar Block: A squared or rectangular block of building stone. Large finished stone block, which is set face bedded; often incorporated into facades of mausoleums, crypts, and historic masonry structures.

Basalt: A dark, dense volcanic rock difficult to shape.

Bed: In rock, the flat surface of a stone parallel to its stratification.

Bed Joint: The horizontal layer of mortar on which a masonry unit is laid

Building Stone: Stone used on vertical applications such as site walls, building facades, retaining walls, etc.

Cobblestone: Cobbles are roughly rounded rocks usually between 2.5”-18” that have historically been used for paving. Today cobbles have taken a life of their own and are used to decorate a landscape setting. Due to their naturally tumbled appearance, cobbles are commonly used to simulate a stream bed or to create natural looking borders along plantings.

Course: One of the continuous horizontal layers (rows) of masonry that forms a structure.

Crushed Rock: Stone that has been crushed and graded by screens to certain size classes. It is widely used in concrete and as a surfacing for roads, driveways, and landscaping.

Decomposed Gravel or D.G.: A granular stone surfacing material usually consisting of particle sizes ranging from 3/8” down to rock dust. This mixture of sizes allows for the correct blend of large particles “strength”, medium sizes “space filler”, and fines “binders”, ideally suited for stable surface once wet and compacted and work great for low traffic walkways, driveways, garden trails, or xeriscape ground cover.

Delimitation: Separation of stone layers along its bedding planes.

Dressed stone: A stone masonry unit which has been squared and shaped for precise fit with other stones. Undressed stone has naturally rough and irregular shapes.

Dry-Stack: Stonework with mortar recessed so that it is invisible.

Dry Stone Wall: A stone wall built without mortar.

Efflorescence: The white or grayish crust sometimes formed on the surface of masonry or stone, often as calcium sulfate. It is caused by the leeching-out of soluble chemical salts, from the stone, brick or mortar joints through the forces of capillary action and evaporation.

Exposed Aggregate Concrete: There are three different methods for incorporating the decorative aggregate into concrete slabs for later exposure:

1) Seed the aggregate onto the surface-The most commonly used method is to seed the decorative aggregate onto the slab surface immediately after the concrete has been placed, struck off, and bull floated. This involves sprinkling the aggregate by hand or shovel uniformly onto the surface and then embedding it with a bull float or darby until it's completely covered by a thin layer of cement paste.

2) Mix the aggregate into the concrete-You can also have the ready-mix producer put the decorative aggregate right into the concrete mix during batching, which eliminates the step of seeding it onto the surface after concrete placement. However, depending on the cost of the aggregate you choose, this method can be more expensive than seeding because it requires using greater quantities of decorative aggregate.

3) Put the aggregate into a thin topping-Another alternative is to place a thin topping course of concrete containing the decorative aggregate over a base slab of conventional concrete. The topping can range in thickness from 1 to 2 inches, depending on the aggregate size. This method generally works best when smaller decorative aggregates are specified.

In all instances After a time of curing, the unhardened layer of matrix at the surface of the panel is removed by a high pressure water washing, thus, exposing the aggregate used in the concrete. Because of its durability and skid resistance, an exposed aggregate finish is ideal for most flatwork

Flagstone: Stratified stone that is split into thin slabs suitable for paving surfaces such as walkways, driveways, patios, etc. 

Fieldstone: Rough uncut stones as they are picked from a field.

Igneous Rock: Rock formed as molten magma cools and hardens under ground. Granite is the most common example.

Ledgestone: Pattern of stonework utilizing horizontal joints.

Limestone: A sedimentary rock formed from shells and organic sea matter. If undergoes metamorphosis becomes marble. Limestone was often used in nineteenth century monuments as a base. May be difficult to distinguish from marble, but tends to be grayer in color then the originally white marble.

Lintel: A horizontal support for masonry or a stone spanning an opening; A horizontal beam, over a door or window which carries the weight of the wall above.


Metamorphic Rock: Rock formed or changed by heat and compression. Formed under high pressure and heat over a long period of time. Examples include: Limestone becomes marble, shale becomes slate, and some sandstones become quartzite.

MOH’s Hardness Scale: A scale devised by the Austrian mineralogist Friedrich Mohs that measures the hardness of mineral by scratching. It is based on a scale which ranges form one to ten. Talc represents the number one, with diamond being at the top of the scale, as a ten in hardness.

Mortar: A mixture of Portland cement and sand, with other possible ingredients. It is used chiefly for bonding masonry units together.

Natural Bed: The surface of a stone, parallel to its stratification.

Natural Stone Thin Veneer: Technological advances in stone fabrication have allowed many natural stone products to be fabricated to only 3/4" to 1 1/2" thick that can be adhered to a conventionally framed structure with standard masonry cement. This eliminates the need for any additional foundations. Thin cut natural stone is the ideal material when weight or space limitations are a problem. It is installed in the same way as manufactured stone. and is a less expensive option to full bed stone veneers.

Quartzite: Metamorphic sandstone. A harder, denser sandstone.

Random ashlar: uses rectangular stones in discontinuous courses. Coursed ashlar uses rectangular stones of the same height in each horizontal course, but each course may vary in height. Broken rangework arranges ashlar units into horizontal courses of varying heights, which may be divided into horizontal groups at various intervals.

Rake Joint: To remove some of the mortar from a joint to a uniform depth, before it hardens.
Rip Rap: A permanent, erosion-resistant ground cover of large, loose, angular stone with filter fabric or granular underling.

1. To protect the soil from the erosive forces of concentrated runoff.
2. To slow the velocity of concentrated runoff while enhancing the potential for infiltration.
3. To stabilize slopes with seepage problems and/or non-cohesive soils.


2. To slow the velocity of concentrated runoff while enhancing the potential for infilitration

Rubble: Masonry construction using stones of irregular shape and size. A random rubble wall has discontinuous courses and may include smaller garrets, small stones used to wedge larger ones into position or fill gaps. A coursed rubble wall is more organized and built to a level course at various intervals. A squared rubble wall is built of roughly squared stones of varying size which are brought to level courses every third of fourth stone.

Running Bond: This is the same as common bond, with continuous horizontal joints, but the vertical joints are offset or inline.

Sandstone: A sedimentary rock made up of compressed sand.

Scarify: To make scratches in mortar or cement, so the next coat has a stronger bond.


Sedimentary Rock: Rock that forms at the Earths surface. It consists of layers or rock fragments or other substances that have been deposited on top of each other. Examples include; lake and river beds become sandstone, sea beds become limestone.


Scratch Coat: The first coat in infill, stucco, or plaster.

Shale: Thinly layered soft stone of clay origin. Becomes slate if undergoes metamorphosis.

“Shot” Stone: Stone quarried with explosives.

Slate: A hard durable rock which comes from metamorphic shale composed mainly of clay. Formed in layers it sometimes delaminates along its bedding planes.

Soldier Course: A course of brick laid with the brick standing on edge with the thin side on the face

Split Face: Stone which is produced by sawing top and bottom beds to a desired height +/- 1/8”, then placing the slab in a hydraulic press “Guillotine”. The Hydraulic press has upper and lower teeth mounted in a straight row on jaws one above the other. As pressure is applied, the stone will separate from the slab at its weakest points, thus producing a naturally rough surface. The break produces a slight concave or convex shape. The stone is cut to length in the field by the installer. The face may be dressed and the ends finished the installer. 

Tie-Stone: A long stone which extends across a wall.

Veneer: A layer or bricks or stones that serve as a facing.

Wedges: Stone chips used for leveling or metal tools used in conjunction with feathers to split stone by hammering on, when used in groups along a row.

Weep Holes: The openings made in mortar joints that facilitate drainage of built-up moisture.