(This plant comes in a 3.5" pot. You will receive a very similar plant to the one in the picture. It may or may not be blooming at the time of your purchase. The plant is shipped in its pot to prevent any damage to the roots).
Mammillaria geminispina is a fairly easy plant to grow, it doesn't require any special treatment, but needs as much light as possible. This Mammillaria gets only better looking with age.
Recommended temperature zone: USDA: 10
Frost tolerance: Hardy to 28°F (-2°C)
Minimum avg. temperature: 50°F (10°C)
Sun exposure: Light shade to full sun elsewhere
Origin: Central Mexico (Hidalgo state)
Watering needs: Regular water in summer
Propagation: Seeds, the best clones are propagated by offset.
Some of the information in this description has been found at desert-tropicals.com, llifle.com and cactus-art.biz