Glossary of Stone-Related Terms

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H

HACKING: The procedure of stacking brick in a kiln or a kiln car. Or, laying brick with the bottom edge set in from the plane surface of the wall.

HAIRLINE CRACKING: Random pattern of superficial cracking in an exposed concrete surface. Usually surface openings of 20 mils or less.

HALITE: Rock salt; sodium chloride; a sedimentary rock.

HALF BULL NOSE: A convex semicircular molding used on exposed edges or stone units such as stair treads, tops and window stools.

HALF ROUND: An exposed edge or molding with a semi-circular section or radii.

HAND CUT RANDOM RECTANGULAR: A pattern where all the stone is hand cut into squares and rectangles; joints are fairly consistent. Similar to sawed-bed ashlar in appearance.

HAND OR MACHINE PITCH-FACED ROCK-FACED: A finish given to both veneer stone and cutting stock. This is created by establishing a straight line back from the irregular face of the stone. Proper tools are then used to cut along the tile line leaving a straight arris and the intended rustic finish on the face.

HARD-BURNED: Nearly vitrified clay products that have been fired at high temperatures.

HARDNESS: A quality of stone determined by ASTM C241 test.

HEAD: The end of a stone which has been tooled to match the face of the stone. Heads are used at outside corners, windows, door jams, or any place where the veneering will be visible from the side.

HEAD JOINT: The vertical mortar joint between ends of masonry units. Also called a cross-joint or a vertical joint.

HEADER: A masonry unit that overlaps two or more adjacent wythes of masonry to tie them together. Also called a bonder.

Blind header: A concealed brick header in the interior of a wall, not showing on

the face.

Clipped header: A bat placed to look like a header for purposes of establishing a

pattern ; also called a false header.

Flare or Flashed Header: A header of darker color than the field of the wall.

HEADED COURSE: A continuous course of header brick; also called heading course.

HEADSTONE: A priciple stone, as in keystone or cornerstone.

HEARTH: That part of the floor of a room made of stone on which the fire is made or above is a stove, fireplace, furnace, etc…

HEMIHYDRATE: A hydrate which contains one-half of a molecule of water compared to one molecule of the principal element or compound forming the hydrate.

HERRINGBONE: A pattern of setting in which the units are laid aslant, with the direction of incline reversing in alternate courses, forming a zigzag effect.

HEWN STONE: To rough form by mallet and chisel.

HIGH-STRENGTH ADHESIVE: A bonding agent of high ultimate strength used to join individual pieces of stone into pre-assembled units.

HOLES: Sinkages in the top beds of stones to engage Lewis pins for hoisting.

HOLLOW BRICK UNIT: A brick unit in which the net cross-sectional area in any plane parallel to the bearing surface is less than 75% of its gross cross-sectional area measured in the same plane.

HOLLOW WALL: A cavity wall, usually exterior, built in two separate parts, structurally connected as necessity with space between for checking the passage of water, or for better insulation created by the closed air space.

HONED/ HONE FINISH: A very fine, satin smooth finish on stone. This is the last step before polishing. A super fine smooth finish with little or no gloss. Recommended for commercial floors.

HORNBLENDE: A group of minerals including calcium, iron, magnesium, and aluminum silicates. May be present in igneous stones.

HYDRATE: A mineral formed by the combination of water and some other elements or compounds.

HYDRATED LIME: Quicklime to which sufficient water has been added to convert the oxides to hydroxides.

HYDRAULIC: To harden under (or with) water.

HYDROPHILIC: Substance which absorbs or has exhibited affinity for water.

HYDROPHOBIC: Having no affinity for or is repellent to water. The quality of beading water on a substrate.

HYDROUS: Containing chemically combined water.

HYGROSCOPIC MOISTURE: Water absorbed by hydrophilic porous materials.