According to legend, opal is the luckiest and most magical of all gems because it displays all colors.

• A. Glows with a single color
• B. Is the hardest gemstone
• C. Only reflects light
• D. Displays all colors

Answer: (D)

Opal’s standout idea is its play-of-color—the way light interacts with its internal structure to create a spectrum of hues. This happens because opal’s tiny silica spheres are arranged in a way that diffracts light, rather than simply reflecting it. Move the stone and the colors you see shift and multiply, showing reds, greens, blues, and more. That ability to display many colors at once fits the legend of being lucky and magical, which is why claiming that it displays all colors is the best description.

The other statements don’t fit this gem’s nature. It doesn’t glow with a single color, and opal isn’t the hardest gemstone. Its appearance isn’t just reflection; the hallmark is the diffraction-based color play that reveals a variety of colors from different angles.