Removed flakes exhibit features characteristic of conchoidal fracturing, including striking platforms, bulbs of force, and occasionally eraillures ( small secondary flakes detached from the flake's bulb of force ).
42.
This results in conchoidal fractures, a characteristic of all minerals with no bulbs of force, and occasionally eraillures, which are small secondary flakes detached from the flake's bulb of force.
43.
These cores were river pebbles, or rocks similar to them, that had been struck by a spherical hammerstone to cause conchoidal fractures removing flakes from one surface, creating an edge and often a sharp tip.
44.
Conchoidal fractures often result in a curved breakage surface that resembles the rippling, gradual curves of a mussel shell; the word " conchoid " is derived from the word for this animal ( Greek " konche " ).
45.
They were all made from blades or from microblades ( nearly always of flint ), using the microburin technique ( which implies that it is not possible to conserve the remains of the heel or the conchoidal flakes from the blank ).
46.
It was apparently free from alteration, had specific gravity of 4.28 ( taken on a very pure fragment ), had a bright green chatoyancy at certain angles, and was like glass in its broad obsidian-like conchoidal fracture.
47.
They are transparent and glassy when fresh, albeit with a noticeably subdued'subvitreous'lustre due to the low refractive index, but readily alter to become waxy / greasy and then dull and opaque; they are brittle and break with a conchoidal fracture.
48.
In the course of his investigations, Nicomedes created the Pappus wrote : " Nicomedes trisected any rectilinear angle by means of the conchoidal curves, the construction, order and properties of which he handed down, being himself the discoverer of their peculiar character . ".
