Industrial minerals have a lot of interesting properties and applications.  

The shape of particles gives a lot of different properties to them.  Spherical particles give good flow properties.  Angular particles become less and less fluid.  Spiky particles give the worst flow properties but they are very useful for reinforcing composites.  The aspect ratio determines the spikiness and effectiveness of reinforcing particles.  Wollastonite is an example of an acicular particle, used for reinforcing.  Its effectiveness depends on its aspect ratio.  This is the ratio of length to thickness.  The higher the aspect ratio the better the reinforcing property of the mineral.  Asbestos has the highest aspect ratio of all natural minerals.   It Is probably the most useful mineral on the whole planet.  Then we get flaky minerals.  Clays are flaky minerals with special properties in water.  We call it plasticity and it is the basis of all pottery products.  Mica's are also flaky minerals.  Muscovite is the clear mica which can be used as high temperature glass.  Vermiculite is a mica which if rapidly heated expands dramatically.  The thin dimension of the plate turns into the long dimension of a worm.  Graphite is another flaky mineral and is useful in lubrication.  Graphene is the single atom thick graphite crystal which has very remarkable engineering properties.  The most irregular shaped particles are found in diatomite.  Diatomite is composed of the skeletons of microorganisms living in the sea.  The commonest industrial mineral is sand.  Sand is usually composed almost exclusively of quartz.  If you shatter a piece of quarts it becomes very sharp particles.  If you roll these particles around on the beach for hundreds of years they become more rounded.  Sharp sand is good for making roof tiles and round sand is good for making foundry moulds.

Angle of repose is determined largely by particle shape.  If you pour minerals onto a flat surface, spherical particles will spread out into a layer of a single particle thick.  The more irregular the shape, the more the particles stack up on top of each other.  The angle of the side of the pile is called the angle of repose.  A high angle of repose may cause clogging of feeding systems, eg. hopper valves.

Density is another property of industrial minerals.  Magnetite is very heavy and can be used to make fluids of different densities which are used in the separation of coal from shale.  Barytes, also called barite or blanc fixe is a mineral of barium sulphate which has a very high density.  It is popular in paints in the USA where paint is sold in pounds but never used in South Africa where paint is sold in litres.

Streak is the colour left behind when you scratch a mineral on a rough surface.  This is the property used by blackboard chalk which is actually made of gypsum and boilermakers chalk which is made of talc.

Colour is another property of industrial minerals.  The finer you mill them the more effective they become as pigments.  Colour may change with fine milling.

Electrical conductivity is an unusual property of minerals.  Zircon has an extremely low electrical conductivity and this property is used in separating it from other dense minerals.  Zircon is used in electrical insulation paints and certain industrial ceramics.

Refractive index is another property of industrial minerals.  Zircon has a very high refractive index and is used as an opacifier in ceramic glazes.  Titanium oxide is the most important white pigment.  You can’t use it in glazes which contain iron, because it reacts to form ilmenite which is the one of darkest, most opaque of all minerals.

Hardness is an important property of industrial minerals.  Hardness is expressed as a number from 1 to 10 on the Mohs scale.  Industrial diamonds are number 10 on the Mohs scale.  Silicon carbide is a synthetic mineral with a hardness of 9,5.  Corundum is number 9 on the Mohs scale and is used in abrasives like sandpaper.  Sandpaper requires all particles to be of the same size.  There are various complex measurements of particle size used in the abrasive industry and in the foundry sand industry.  Talc and gypsum are particularly soft minerals.  The abrasiveness of industrial minerals is affected not only by the hardness but also by the particle shape.  Quartz is not particularly hard but it is particularly sharp and therefore very abrasive.  Shot blasting makes use of various industrial mineral properties including toughness.

Cleavage is the way that minerals break.  Calcite for example has a cubic cleavage and makes it easy to mill into fine particles and therefore cheap to mill into fine particles.  Glass, and some minerals like quartz have a conchoidal fracture, giving them sharp edges.  

Magnetism is a rare property of industrial minerals that is found in magnetite.  This property allows magnetite to be separated from mud when it has been used for making a dense medium for example in coal separation.  Magnetite looks like a very cheap material to use to obtain high density but its magnetism imparts terrible flow properties.

Wetting angle / wettability is another important property.  Graphite, coal and silicon carbide are not easily wetted by water.  Chemicals can be used to modify this.  Some chemicals cause sulphides to become pneumophilic, i.e. gas bubbles adhere to them, and this can be used to separate them in beneficiation processes called froth flotation.

It is important to understand the properties of minerals.  If you don’t, you might see for example wollastonite in a formulation and buy cheap Chinese wollastonite which is not acicular and find that the product doesn’t work.  You need to get data sheets on all the materials you use and verify them as far as economically possible.  Most QA systems require a “Certificate of conformance” with every batch.  Many suppliers submit these but leave out the important properties.  The author has seen examples where the QA system is conforming but the paperwork has no practical value.  The author uses a very simple system of tiny Polytops bottles of conforming samples, and in some cases of limits of quality obtained over the years.  When a batch arrives, a Polytops sample, three quarters full is taken and compared with the standard sample.  At a glance you see the colour, which readily reveals contamination.  You can see the grading (Particle size distribution) fairly clearly.  By rotating the samples you can see the angle of repose, flow and cohesion, which are affected by particle size, shape and dampness.   The author has a system of QA buckets for aggregates.  Every time there is a quality problem, you can quickly identify it by making a small sample of your product and substituting from your QA buckets starting with the most suspect material, until you get it to work.  This takes hours.  Without it, identifying the problem can take days or weeks.