Imagine how much deeper the oceans would be without it!
if the crust were a sponge, imagine how much water the earth is holding!
That depends on what your definition of “is” is…
quartz is SiO[sub]2[/sub], yes, but it’s not *just *that - it’s SiO[sub]2[/sub] with a specific crystal structure. You can’t compare it to chalcedony, you need to compare it to e.g. moganite or cristobalite. Just like jasper, for instance, isn’t *just *SiO[sub]2[/sub] either - it has to be opaque, and coloured by inclusions. Granted, there’s no *clear *distinction between some of these categories - is a given piece flint or chert, for instance? Well, if it’s microcrystalline, it’s *always *chert, but it’s also flint if it’s found in chalk or marl. For some of them, there’s a great degree of specificity, and for others, while there’s some leeway, it’s not infinite.
Basically, there’s a degree of mixing-up of minerals (e.g. quartz, moganite) with rocks (e.g. chert, chalcedony) with subtypes of both(e.g. amethyst is a kind of quartz, flint is a kind of chert) happening.
Combine that with the 20% of people named Bob and you get…