OK - it was going to be either Fluorite or Quartz for many of the same reasons - but I've settled on Quartz.
And the reasons...
Above all, Quartz is simple and common. (I tend towards VERY common when I've been around drillers for too long!)
Quartz is hard (7 on Moh's scale) but brittle. It can thus be scratched by harder minerals but, strike it hard and it will fracture.
When fractured, Quartz displays a complex pattern on its surface.
Quartz dsiplays triboluminescence - that is, it sparks orange or yellow when struck.
It is a popular mineral and has a variety of uses. To some it is a gem, to others it finds use as a semi precious stone and to yet others, it is useful in industrial applications. Very few people however have little use for it.
Although presenting itself in one seemingly simple form (hexagonal), in actual fact Quartz's crystal structure is extremely complicated.
Whilst it has a variety of forms and colours, Quartz is generally transparent. A good honest sort of mineral you could say.
stales
