Amid a plummeting stock market, self-driving cars running amok, and Mark Zuckerberg buying a house in Northwest, another sign of end times has arrived in Washington, DC: A diamond, the color of blood.

Blood gets its color from hemoglobin, the protein in your red blood cells that carries oxygen throughout your body. When hemoglobin binds with oxygen, it turns bright red. When it drops off that ...

Laid out like an orchestra in a quiet gallery room, 40 colorful gems have one of the planet’s most distinguished conductors: ...