Smithsonite is a rare member of the Calcite mineral group, named in honor of James Smithson, the founder of the Smithsonian Institution. It occurs as a secondary mineral in the oxidation zone of Zinc-bearing ore deposits. It has an incredible variety of colors including apple green, blue-green, lavender, purple, yellow, white, brown, blue, orange, peach, colorless, gray, pink and red. One of its exceptional properties is its silky to pearly luster. Common mineral associations include Azurite, Malachite, Cerussite, Hemimorphite, Quartz, Fluorite and Galena.

The crystal system for Smithsonite is hexagonal. Though rare, crystals are rhombohedral and scalenohedral, usually with curved faces. More common forms include globular, botryoidal, stalactitic, encrusting, massive and lenticular (flattened nodules in a lens-like shape).

Quality specimens of Smithsonite are found in limited localities, including Australia, Greece, Italy, Mexico, the USA (New Mexico, Colorado, Arkansas) and Zambia.