November 10 – Anniversary of a Big-Time Gift

Posted on November 10, 2018

The Hope Diamond is one of the most famous diamonds in the world. I wrote about it (or at least the earlier version of the diamond, called the "French Blue") in another post.

On this date in 1958, jeweler Harry Winston donated this large, unusually blue diamond to the Smithsonian Natural History Museum, where it can be seen by all...for free!

I want to talk about two aspects of the diamond: the science of it and the silliness of it.

The silliness

The diamond is supposed to be cursed - whoever owns it or wears it is supposed to have misfortune or tragedy. I assumed that this rumor was the result of a couple of tragic incidents that were cherry-picked without mentioning owners and wearers who were perfectly fine during and shortly after their time with the diamond. But instead there is evidence that the tragic stories were simply made up in order to create a "buzz" about the jewel, and shroud it in mystery, and therefore raise the worth of the jewel. (I would think that the rumor of a curse would lower the worth of the jewel, but apparently not!) 

The long list of people who had encountered the diamond and then were ....well, torn to pieces by a mob of people, in one case, and by a pack of wild dogs, in the other - people who were murdered, who were killed in a revolution, who committed suicide - people who died in "misery and want" or were hanged or or or ... Apparently there's no evidence that these stories, published in the New York Times, were true or even partly true!

The folks at the Smithsonian Museum have pointed out that the Hope Diamond has only brought good things to the museum, and has led to zero problems or tragedies.

The science

Diamonds are usually clear, but other colors can occur: can you imagine gray, white, blue, yellow, orange, red, green, pink, purple, brown, or black diamonds? Colored diamonds either include impurities or have structural imperfections - it is the pure and perfect diamonds that are perfectly transparent and colorless.

Diamonds are either pure carbon or mostly pure carbon, but then again, so is graphite - the dark gray stuff inside our pencils! (Coal and charcoal are mostly carbon, and they are black, but they have a lot more other sorts of atoms than do diamonds and graphite.) The difference between pure-carbon diamonds and pure-carbon graphite is the arrangement of those carbon atoms. Diamond atoms have super strong bonds, and all of the carbon atoms are in tight formations of perfect tetrahedra. Graphite atoms, on the other hand, have some strong bonds but also some looser bonds. This means that the atoms form sheets that slide apart from one another.

Left, diamond and its crystal structure.

Right, graphite and its structure.

Those structural differences lead to diamonds being really hard as well as clear, and graphite being soft as well as dark. 

Uncut blue diamond
The Hope Diamond is blue because it has boron atoms. Not many boron atoms, mind you - there is about one boron atom per a million carbon atoms in a blue diamond! And the very, very, very occasional boron atom has one fewer electron than its carbon neighbors, so it can't form the same four perfect bonds. This means that there is a bit of freed-up electrons in a blue diamond - electrons that can interact with light and give the diamond a blue color!

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