Emerald Tumbled Medium

Among the books, decks, and stones on 14th Street is this tumbled stone: Emerald Tumbled Medium (shop SKU EXEMR).

Emerald is the green variety of beryl (beryllium aluminum silicate), colored by chromium or vanadium, and is sometimes found in mica schist. These are mineral specimens as described on the listing, not faceted gemstones unless the title says otherwise. In crystal traditions, emerald is associated with the heart. Those ideas belong to folklore and personal practice, not to any medical claim.

Tumbled stones are polished in a drum, which softens sharp edges and brings out color. Natural stones vary in color, clarity, and shape, so the piece you receive will have its own character even when the weight, grade, or size is listed.

• SKU: EXEMR

See it at Namaste Bookshop, 2 West 14th Street near Union Square in New York City, or order online.