See hollandite.

Precipitation from solution of one solid phase on another.

A reaction that involves more than one physical state (i.e., solid, liquid, gas).
Cf., homogeneous reaction

An obsolete varietal term for biotite.

Expandable 2:1 clays (e.g. smectite, vermiculite) treated with solutions of the quaternary alkylammonium salt, hexadecyltrimethylammonium (HDTMA) bromide (also called cetyltrimethylammonium bromide), form organophilic-type organoclay. HDTMA organoclay can effectively remove organic contaminants, such as toluene, from water; see Boyd et al. (1988).
Cf., adsorptive organoclays, organoclay, organophilic-type organoclay

A poorly defined material, possibly a mica.

In geotechnical engineering, high-activity clays have activities that range from about >1 to 7+, with smectitic clays (i.e., smectite or interstratifications with a smectite-like component) being the most common having activities near 3 (where Ca-saturated, or in high salinity environments) to 7+ (where Na-dominated and at low salinity).
See activity, clay; low-activity clays; quick clays

Hinckley (1963) attempted to define the “crystallinity” of kaolinite by describing changes in the powder X-ray diffraction pattern for various samples of kaolinite. The procedure, however, does not quantify the diversity of defects present and, if the procedure is used, it should not be characterized as a “crystallinity” index.
See also, Plancon and Zacharie (1990); Guggenheim et al. (2002).
Cf., crystalline, crystallinity index, Kübler index, Arkai index

Hisingerite is a natural ferric kaolin, analogous to halloysite, that forms partly spherical to spherical morphologies approximately 60-200 Å in diameter.

Hollandite (Post et al., 1982) is a manganese oxide mineral within the hollandite supergroup (Biagioni et al., 2012) with a general chemical composition of A_0-2B₈(O,OH)₁₆, where A = Ba²⁺ and B = (Mn⁴⁺₆Mn³⁺₂) in hollandite. The B cations form edge sharing double chains of B-O octahedra, with each double chain forming a wall of a four-sided tunnel. The large A cations, in ideally eight-coordinated sites, reside in the tunnel and offset any undersaturated charge on the octahedra. The supergroup is divided further into the coronadite group (Mn⁴⁺ dominates the B cations and includes hollandite) and the priderite group (Ti⁴⁺ dominates). Other minerals in the coronadite group include (A cations) K⁺ in cryptomelane [ideally B = (Mn⁴⁺₇Mn³⁺)], Sr²⁺ in strontiomelane [ideally Sr(Mn⁴⁺₆Mn³⁺₂)O₁₆], Pb²⁺ in coronadite [ideally B = (Mn⁴⁺₆Mn³⁺₂)], and Na⁺ in manjiroite [ideally B = (Mn⁴⁺₇Mn³⁺)]. Ferrihollandite is BaMn⁴⁺₆Fe³⁺₂O₁₆. Other B cations in natural samples can include Ti⁴⁺, Fe³⁺, Al³⁺, Si⁴⁺, Mg²⁺ or additionally, in synthetic phases, Zn²⁺, In⁴⁺, Ni, Cr, and many others. Likewise, A-cation substitutions include Ca, Sr, H₂O, vacancies, etc. Priderite is (K,Ba)_0-2(Ti⁴⁺₇Fe³⁺)₈O₁₆ and other members of the priderite group are redledgeite [Ba(Ti⁴⁺₆Cr³⁺₂)O₁₆], mannardite [Ba(Ti⁴⁺₆V³⁺₂)O₁₆ . H₂O], henrymeyerite [Ba(Ti⁴⁺₇Fe²⁺)O₁₆]. The presence or absence of H₂O does not define a hollandite-like species. Hollandite-supergroup mineralization occurs in oxidized zones of manganese ores, in hydrothermal deposits, and in some soils. The tunnel topology allows for these minerals to be good ionic conductors for batteries.