If someone were to ask you, "What is your favourate ROCK ?" One might imagine responses such as emeralds, sapphires, rubies and please don't say it? the object of the greatest commercial propaganda campaign ever; The de Beers ethos that diamonds are forever..... and a women's best friend. But perhaps figuratively, your rock star maybe George Harrison, Kurt Cobain or the Guess jeans girl. Sigh......!
However, for me, my favourate rock would have to be the Schist's containing alumino-silicate polymorphs. Errghhh !!!! Sound to chemistry? Please don't barf because truly they are the origin of many materials one uses on a daily basis. Also producing wonders of crystallisation like this kyanite in the photo below.
Polymorphs are elements that exist in three temperature and pressure phases, with perhaps the most beautiful, water, inhabiting, solid ice, liquid aqua and gas steam. So too, some Alumino-silicates exist in three temperature and pressure phases of solid crystal kyanite, sillimanite and andalusite. Kyanite having a pretty blue/purple oblongs, sillimanite having cream coloured flaky fingers and andalusite having grey/pink granule spheres.
The photo below, by the Smithsonian Institute a prestigious American museum, shows the three solid examples of an alumino silicate polymorph described in the last paragraph. Also it illustrates the importance of, attention to detail, in scientific communication. Can anyone see the mistake in this photo? While it provides an excellent graphic explanation, the rock photos need to be rotated counter clockwise, one place, for the diagram to be correct. Please click on the highlighted link above for further investigation.
To me alumino silicate polymorphs are quite pretty? But only sometimes because usually they are just contained in a slab of squeezed and melted solidified "goo" of rock schist. However it is at the boundaries and gradations of the pressure and temperature regimes of the alumino-silicate polymorphs where geologists and metallurgists find the ores containing copper, lead and silver, amongst other elements.Besides the European spelling of English, can anyone see any lack of, attention to detail, in this post? because it is usually the critic who makes the worst error.
