A heterogeneous composition for use as rock dust is disclosed. The heterogeneous composition includes a fine, wet ground inorganic particulate material treated with at least one fatty acid, a salt thereof, or an ester thereof, and a coarse, untreated, dry ground inorganic particulate material. Also disclosed is a heterogeneous composition including coal dust and mine rock dust including a fine, wet ground inorganic particulate material treated with at least one fatty acid, a salt thereof, or an ester thereof, and a coarse, untreated, dry ground inorganic particulate material. The amount of mine rock dust may be sufficient to render the coal dust explosively inert. The fine, treated, wet ground inorganic particulate material may be calcium carbonate. The coarse, untreated inorganic particulate material may be calcium carbonate. The fatty acid may be stearic acid.

The invention provides an aqueous ink containing a coloring material, wherein the coloring material is a self-dispersible pigment in which a functional group containing another atomic group and an anionic group such as a carboxylic acid group, a sulfonic acid group, a phosphoric acid group or a phosphonic acid group are bonded to a particle surface of a pigment such as carbon black or an organic pigment, and a standard deviation of an introduced amount of the functional group is 0.0380 or less.

The present invention relates to a method for producing a zinc oxide-functionalized calcium carbonate composite, a zinc oxide-functionalized calcium carbonate composite obtainable by a method, an article comprising the zinc oxide-functionalized calcium carbonate composite as well as the use of the zinc oxide-functionalized calcium carbonate composite in an aqueous preparation or in a solid article.