This pear-shaped, D-color, flawless diamond of 50.52 carats was just sold for $9.5 million at a Christie's auction. At 50 carats of diamonds, it's not clear what you'd actually do with such a massive gem, but I'm pretty sure the new owner isn't worried about that right now. A diamond like this is so absolutely rare and speaks to the fundamental reason why we humans have this fascination with diamonds. Rarity.

Take it down a notch and speak of 1 carat diamonds for a second. Do you know that you need to mine up to 20 tons of rock to find just one carat of gem quality diamond? (The majority of the diamonds that are unearthed are of a brownish color and are spotted with inclusions. They are used for industrial purposes.)

So really what I'm saying is that the same driving force that drives millions of Americans to buy 1 carats is what propels someone to own a 50 carat diamond for almost $10 million. It's just heightened and at a different scale due to the latter person's financial abilities. They want the same thing --rarity, status among their social peers, etc. -- just on a different level.