by Chester » Thu Oct 05, 2017 12:53 pm
1) Asbestos is a type of evaporate deposit, formed of tiny fibres. These fibres can enter peoples lungs and form nasty infections that have lead to deaths. Having said that it's not too common so compared to other dangers (food poisoning) it's not a major concern - but it still ought to be removed from buildings!
2) Gems come in different colours due to different elements in the gems crystal structure. Without going into complex mineralogy some atoms of say iron will replace some of those of silica in, say quartz and form a different colour gem as a result of some nifty physical properties.
3) a mineral can 'become' an ore if we find a need for it, or a way to get something useful out of it. geologically you get ores by a number of means including hydrothermal activity (replacing some of the minerals with nice useful ones) and magmatism.
4) Crystal form is formed via the crystals atomic structure, while cleavage is formed via the angle between the bonds in the atoms in the mineral
5 Excess stress (and impurities)
6) I'd go for quartz and feldspar, but it depends on what you define as the surface