Thelocactus rinconensis
Native range: Northeast Mexico
Known names: N/A
Hardiness: Can take down to 32°F if kept dry in winter.
Mature Size: Grows slowly to ~4" inches wide, ~4" tall.
Light: Bright direct sun, Half day sun- avoid afternoon sun. 
Water: Water during summer (let soil dry out completely), keep pretty dry during winter.
Soil: Cactus/Succulent mix
Dormancy Period: Winter
Pet-Safe: No
Plant Size: Grown in 2" pot, shipped semi bare root
 
Powder blue cactus, spines are highly variable from plant to plant (color, shape, and size).
Flowers can also vary from white to pinkish, to yellowish.