Monday, September 20, 2010

Why are minerals important?

The other day, someone (a non-geologist scientist) asked why minerals were important, and the earth can’t just be thought of as a homogenous lump of elements. Here in myopic subfield land, it sounds like a stupid question, but mineralogy and petrology do not exactly have the highest profile amount the general population. The man on the street thinks a petrologist is someone who works for Exxon. Word thinks the petrologist is a misspelling of pathologist. So I took a quick look at my old undergrad petrology textbook, and it doesn’t even consider the question. The introduction starts, “Igneous rocks are formed by the cooling and crystallization of magma, which is molten rock that”.
It then goes into definitions, and there is no attempt to even sell the field.

On a related note, when I left the ANU back in ’07, they were performing a curriculum review, and one of the ideas floated was to ditch mineralogy as a core required class. So even Earth Scientists (evidently ‘geologist’ is old fashioned, and creates insecurity among our colleagues who don’t actually know what a rock is) underappreciate the organization of atoms into ordered structures.

I got into petrology because I thought it was cool, and then strayed into geochem by inertia. But I’ve never really defended its importance before. So I’ll let all you lurkers speak up here. Consider this a hard rock version of the introduce yourself post. What is great about mineralogy and petrology, and how do you explain petrology in a sentence to someone who thinks you work for Exxon?


Silver Fox said...

This hard rocker (not exactly a petrologist or mineralogist but a geologist who uses both, especially the latter, at work on a daily basis), says "Yikes!" to ditching mineralogy.

When logging core, estimating percentages of certain minerals (a very basic function of mineralogy), can result in estimation of ore grade, which many mines find useful.

Petrology: the *real* study of rocks. I also describe geology as the study of rocks to those who don't know, perhaps because of my own personal bias.

Chris Phoenix said...

It's like asking "Why are street signs important" or "Why can't we see the biosphere as just a scum of protoplasm."

Christie Rowe said...

the physical and chemical properties of a rock are strongly dependent on the minerals (and microstructures) present. The mineralogy and microstructure are dependent on both the bulk chemistry and the rock's history. So the bulk chemistry alone is not a predictor of rock strength, permeability, or any other useful engineering parameters.