Book Review: Stoned by Aja Raden

For the most part I really enjoyed this book. It’s a fun read with some excellent lines.* y648

 

I appreciate her efforts to clearly explain things as vastly different as the geological and biological processes that create gemstones and pearls, and different concepts of value to the psychology of want and envy and their roles both in marketing and the shaping of the political world.

 

One thing that irked me about it is the small inaccurate throwaway lines.

 

For example, she had one regarding Romans and how something they did wasn’t too smart for the people who invented indoor plumbing. The earliest culture we know had indoor plumbing was the Minoan, who flourished centuries before Rome.

 

In her discussion of green she mentions the sacred nature of the green man in Celtic religion, there isn’t enough known about Celtic religion to even know what they believed about a green man or to be sure it dates back that far. A lot of ‘knowledge’ about Celtic religion is essentially backdated new age belief.

 

It’s hardly a big deal (you could completely cut these bits without impacting the book) but the casual inaccuracies made me wonder a little bit about the larger historical discourse. Especially since her biographical blub says she studied ancient history and there are a lot of wonderful stories in here that I hope I can trust! The pearl portion is a fabulous mix of politics, gossip and family hatred as really only Tudors could do it.

 

She has a lovely section on how well before diamonds were a twinkle in the market’s eye emeralds were *the* stone to have all over the world.

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What really caught me was the explanation why they occur naturally in so few places: plate tectonics. (They’re found in Columbia, Brazil, Egypt, and Zimbabwe.) I loved learning about the chemistry behind gemstones because it’s a difficult thing to find explained in plain language!

 

As I’d mentioned previously emerald is a type of beryl crystal. So we have crystals where the trace element contamination determines the color. Iron ions can make the crystals blue and we call it aquamarine. Manganese makes pinks that we call Morganite. It comes in whites and yellows too-the contaminations make for a rainbow of shades. But the only officially accepted emerald is beryl made green through traces of chromium.

 

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A rainbow of beryl gemstones. (GIA Gem Project)

 

And that’s what makes emeralds so rare. Both beryllium and chromium are comparatively rare elements. But plenty of gems have rare elements. The difficult part is that these two usually exist in different places in the earth’s crust. Beryl is normally found in newer rocks formed from cooling magma, the type we find on land. Chromium is found in trace amounts in very ancient rocks like those that make up the earth’s crust over the sea floor.

 

For emeralds to form two very different types of rocks need to meet with intense heat and pressure.

 

In her words “Two different continental plates smash together. The continental shelf is crumpled and pushed upward into aged peaks, while superheated water and dissolved minerals are forced through every crevice. This is how massive mountain ranges like the Himalayas and the Andes were formed. This is also how emeralds are created.”

 emerald_crystal_muzo_colombia

Chromium was present in these dissolved minerals, and while forced through the newer rock some replaced the aluminum of still growing beryl crystals, creating emeralds.

 

Take a look at her book to read about the influence of emeralds on things as disparate as the Age of Exploration, the terrible conquest of the Americas, and the mess that our financial systems are today.

 

*Plus almost enough snarky as well as informational footnotes to compete with Terry Pratchett…

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Filed under Books, Gems, Natural Science, Uncategorized

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