A cryptocrystalline stone is one that is made up of minute crystals that can only be seen with a microscope.
12.
Chalcedony is a cryptocrystalline form of silica consisting of fine intergrowths of both quartz, and its heliotrope, and jasper.
13.
H�lleflinta under the microscope is very finely crystalline, or even cryptocrystalline, resembling the felsitic matrix of many acid rocks.
14.
It is of moderate hardness occurring occasionally in aggregates of hexagonal crystals occasionally but more commonly in microgranular / cryptocrystalline masses.
15.
A portion of the southwestern flank of Mount Fee comprises no volcanic glass, but rather composed of an abnormal cryptocrystalline matrix.
16.
For example, it lists chalcedony, which is cryptocrystalline, and thus would never exhibit visible crystals ( except as inclusions ).
17.
To avoid this, the term " silicate " may be used to describe the family of cryptocrystalline quartzes that are suitable for knapping.
18.
Cryptocrystalline silicates, such as flint and chert, are sometimes heat-treated in order to improve the flaking properties of the material.
19.
"' Chalcedony "'( ) is a cryptocrystalline form of silica, composed of very fine intergrowths of quartz and moganite.
20.
As well as cryptocrystalline quartz, macrocrystalline quartz ( both vein quartz and rock crystal ) was a commonly used raw material around the globe.
