conchoidal's Usage Examples:

In colour they vary from ash-grey to black, and their fracture is conchoidal.

It shows a conchoidal fracture.

It forms a grey brittle mass, having a conchoidal fracture; it is very deliquescent, combining very energetically with water to form caustic potash.

Occasionally the rounded cracks extend from the matrix into some of the crystals especially those of quartz which have naturally a conchoidal fracture.

Pyrites presents a conchoidal fracture, and a very indistinct cubic cleavage.

The chemical composition of typical obsidians is shown by the following analyses Obsidian, when broken, shows a conchoidal fracture, like that of glass, and yields sharp-edged fragments, which have been used in many localities as arrow-points, spear-heads, knives and razors.

"In colour they vary from ash-grey to black, and their fracture is conchoidal.

Diamond may break with a conchoidal fracture, but the crystals always cleave readily along planes parallel to the octahedron faces: of this property the diamond cutters avail themselves when reducing the stone to the most convenient form for cutting; a sawing process, has, however, now been introduced, which is preferable to that of cleavage.

The fracture is conchoidal, and the material is brittle.

The cleavage is imperfect, but there is a well-marked conchoidal fracture.