Delta:  The high area remaining between successive flake scars.

End shock:  The vibrating force that causes preforms to break in two when struck at or near the base.

Feathered out:  A type of flake termination.

Flake:  The piece of stone intentionally removed when flintknapping.

Flintknapping:  The art of making stone tools such as arrowheads, knife blades, spear points, atlatl points, scrapers, etc, by remove flakes from concodial stone via percussion or pressure flaking.

Flute:  A flake taken from the basel edge that typically extends through the hafting area.  Defining feature of Paleo points such as the Clovis and Folsom.

FOG (Flake-Over-Grind): A process whereby a stone is cut into slabs and then the slabs are cut to shape and contours are ground onto the preform with a diamond wheel.   Facilitates very consistent flake patterns.

Fracture:  A crack or break in the stone, either intentional or unintentional.

Grinder: A grainy material used to prepare edges and platforms (also abrader).  Also a mechanical device use to remove the mass of a stone through grinding.

Ground:  (1) Prepared edge or platform. (2) Contoured by grinder (see FOG).

Hammerstone:  A grainy stone used as a percussion tool to remove flakes.  May sometimes be used as an abrader/grinder.

Hand pad:  A piece of leather or rubber that protects the hand while pressure flaking

Healed fracture:  An old fracture in stone that has been resilicified.

Heat Treating:  A method of applying heat to stones to improve the color and workability. (see 'Heat Treating Guide w/Temperature/Time/Thickness Table' by Jim Miller' in the How-To section)

Hinge Fracture:  One way a flake may terminate; ends in a rounded, upturned hinge-like manner.

Inclusion:  A pocket of undesirable stuff in stone. Can be crystals, concrete, ash, limestone, etc.

Indirect percussion:  A type of percussion flaking that uses two tools where the stone is not struck directly.  Typically a 'punch' and 'hammer' are used.

Ishi Stick:  A long handled pressure flaking tool - attributed to Ishi. ( See 'Instructions for Making Ishi Sticks and/or Pressure Flakers by Jim Keffer' in the How-To section).

Isolated platform:  A carefully prepared percussion platform isolated from the surrounding rock, typically through abrading.

Jasper:  A opaque knappable stone, typically reddish, mustard or brown, but may be found in a variety of colors.

Knapping:  Short for flintknapping.  More common term for those who typically knap stones other that flint/chert.

Lens:  A somewhat flattened piece of chert/flint that formed with rounded edges.

Lenticular:  Having the shape of a double-convex lens.

Leverite:  An UGLY stone that, regardless of whether concodial or not, is not suitable for knapping (or much else).  As in 'Leave 'er right there'.

Master Knapper (PSK Definition)

1. Able to use Abo or Modern Tools and produce excellent points
2. Expert at both Percussion and Pressure Flaking
3. Expert at reproducing most if not all point styles
4. Can knap either rough rock and slabs
5. Can knap all types of conchoidal rock (knappable rock), from obsidian to flint
6. Points are of excellent pattern, symmetry and  aspect ratio
7. Can declare point style/type before beginning and produce excellent example of same from any conchoidal rock using 1 or 2 above from start to finish*
   * This is the real distinguishing feature of a 'Master Knapper'

Nipple:  A pronounced platform, often referring to one located on the basal end for fluting.

Nodule:  A thick, rounded formation of chert/flint.

Notch:  An indentation used for hafting.

Obsidian:  A glass-like rock formed by volcanic activity (volcanic glass).

Overshot:  A flake that travels from edge to edge.

Percussion:  To remove flakes by striking the edge of the stone.

Platform:  The place on the edge of the preform/biface that is struck during precussion flaking.  Also refers to the prepared edge used to apply pressure in pressure flaking.

Punch:  A tool, commonly antler or copper, that has one end placed against the stone and the other end is struck to remove flakes.

Radial crack:  A type of undesirable fracture; often results in broken preform.

Ryolite:  An igneous rock, sometimes knappable, often rough and course.

Scar:  The area on a knapped rock where a flake(s) has been removed.

Serrations:  Tooth-like flaking on the edge.  Not to be confused with 'barbs', they resemble the serrations on a steel knife.

Spall: Verb - 'To Spall' means to break up a large rock into smaller, usable pieces.  Noun - 'A spall' refers to one of those smaller pieces;

Stack:  An anxiety-producing knapping error, usually comprised of a series of hinges and steps.

Step fracture:  One way a flake may terminate;  flake ends in a 'stair-step' type ledge.

Tab:  A naturally occuring flattened piece of chert, typical of Perdernales chert.

Uniface:  A stone tool made by knapping only one side (face).

Vug:  A pocket in knapping material that is usually filled with limestone, although can be hollow.  

Waldorf:  An identifiable flaw in a stone that, if knapped, will most likely create problems.  Declaring a 'Waldorf' is to let other flintknappers know, in advance, that the flaw is in the stone and not the knapper.  Attributed to D.C. Waldorf at a Richardson's Rock Ranch Knap-in.