Test your knowledge with these top questions!
Most natural diamonds reach Earth's surface in which volcanic rock?
Fast-rising magma carried the crystals upward and cooled into pipe-shaped deposits mined today.
Diamonds consist almost entirely of which chemical element?
Graphite in pencil lead is also pure carbon, with atoms arranged in soft sheets rather than a rigid crystal.
What shape defines the classic emerald cut used for emeralds and other gems?
The cut's trimmed corners protect brittle gems, and its long facets highlight color over sparkle.
Which South American country leads the world in high-quality emerald mining?
Colombia's Muzo and Chivor mines have produced fine emeralds for centuries, long before Spanish colonization.
Star sapphires show a six-rayed star because of which optical effect?
Fine needle-like inclusions reflect light into a star that glides across the dome.
Ruby serves as the birthstone for which month?
Jewelers pair July with ruby, while June takes pearl and August takes peridot.
Red corundum earns which separate gem name?
Chromium traces turn corundum red, and dealers reserve the name ruby for that color.
Which Egyptian queen treasured emeralds from mines near the Red Sea?
Ancient Egyptians mined emeralds in the Eastern Desert, and later writers called those workings Cleopatra's mines.
Diamond weight is measured in what small unit?
One carat equals 0.2 grams, so even a two-carat diamond weighs less than half a gram.
In the ruby trade, what does "pigeon's blood" describe?
Dealers use the term for vivid saturated red rubies with little orange or pink.