Anthodite

Anthodites in Skyline Caverns, Virginia.

Anthodites (Greek, "flower cluster") are a rare variety of speleothem (cave formation) that forms in limestone caves.

Description and chemistry

Anthodites are white and grow in flower-like clusters of narrow white aragonite crystals. Composed of calcium-carbonate, anthodites grow approximately one inch every 7,000 years. The mechanism by which anthodites form is debated. One theory, however, is that they grow in a vacuum and that they stop growing when the vacuum is broken.

The largest deposit of anthodites in the world was found in the Skyline Caverns in Front Royal, Virginia. Because of the rarity of these formations, Virginia law imposes a penalty of a $5,000 fine and two years in prison for every inch of an anthodite that is broken off.