Note, clicking on parts of the image itself, or the text, will take you to the descriptions down below. 

TERMINATION VARIATIONS - These are all of the different variations that can occur from the termination of flake, when struck from a core.  Please click here for a more detailed page and description of such terminations. 

COMPRESSION RINGS (Shock Rings, Ripples) - Undulations on the face of an artifact caused from shock waves that run through the piece until the flake is detached from the core.  Compression rings are usually more drastic in materials that knap better (due to heat treating, or just more knappable raw material). 

HATCHURE FISSURES (Fissures, Hatchuring) - Caused from excessive force used in percussion striking.  Often, when knapping, the flake will detach in more than one piece - this is caused by hatchure fissures. 

BULB OF FORCE (Bulb Of Percussion) - The bulbous part of a flake closest to the platform, or where the flake was struck from the core.  Caused from the compression of the rock due to the impact when trying to detach the flake.  It is often called bulb of percussion due to it being more prominent  when the flake is removed with percussion methods than pressure.

ERRAILURE SCAR (Errailure) - A secondary flake scar occuring on the ventral side of a flakes bulb of force.  Errailure scars are caused from using excessive force when trying to detach a flake from the core.  Generally, they are more prevalent in higher quality materials. When struck with great force, the flake will often rebound within itself, causing the secondary flake - Errailure scar.