See pyroxenoid group.

See stilpnomelane.

A crystal habit describing thin, flexible filaments.

In geotechnical engineering, fill is geological material in containment formed by human activities, such as dumping, compaction, and hydraulic deposition (via pumping).

A filler is a solid fine- to very fine-grained, natural or synthetic, organic or inorganic substance that bonds to the active ingredients, e.g. clay minerals, with the following properties:

1. negligible dissolution in the active material and

2. capable of being added to the excipient to reduce the amount of the active ingredients (= cost savings) without a significant reduction in the properties of the active material or to improve its properties. For example, talc and kaolinite are used as fillers in paper, cosmetics, pigments, or varnishes, and smectite is often used as a filler in plastics.

A kaolinitic-rich clay with excellent refractory properties, and the fired product is commonly used as fire bricks. The refractory clays are classed as low, medium, high, and super duty with the latter heat resistant from 1430 to 1804°C. Fire clays are low in alkali, alkali earth, and transition metals. Typically found in association with coal layers.
See refractory material.
Cf., underclay, seat rock

Heat treatment of clay materials that cause partial melting and fusion to create ceramics
Cf., thermal activation

The property of breaking or cleaving into flake-shaped, nearly planar paper-thin fragments. Fissility reflects fabric and texture such as the parallel alignment of clay minerals and phyllosilicates and fine-grain size laminations.
See lamination.

Flame retardancy is the property of an additive that lowers the flammability of a material. Flame retardancy is measured by several standard testing methods, with the most common test being the UL94 test. However, more information is obtained by utilizing a cone calorimeter. Clay/polymer nanocomposites lower the flammability of the polymer significantly in both types of flammability tests. Clay layer-by-layer composites have been shown to greatly lower the flammability of textiles. The flammability of materials for construction and clothing is of particular interest for the interiors of airplanes, commercial and residential construction, home furnishings, children sleepware, and clothing for industrial workers.
Cf., layer-by-layer composites

A descriptive term for tenacity where a mineral may bend without breaking, but does not return to its original shape after the force is released.
Cf., elastic