It is a secondary, low-temperature mineral, associated with annabergite, fluorite, baryte and sphalerite.

Apatite, barite and vermiculite are among the industrially important minerals associated with some carbonatites.

Sepiolite occurs as a secondary mineral associated with serpentine.

Fluorite is a colorful mineral associated with hydrothermal deposits.

Other minerals associated with okenite include apophyllite, gyrolite, prehnite, chalcedony, goosecreekite and many of the other zeolites.

It is an accessory mineral associated with nickel laterite deposits in New Caledonia.

It is a metamorphic mineral associated with the blueschist and greenschist facies.

Generally cinnabar occurs as a vein-filling mineral associated with recent volcanic activity and alkaline hot springs.

Other minerals often associated with hardystonite are franklinite, diopside, andradite garnet, and esperite (fluoresces yellow).

It is found in many localities, associated with lead ores as a secondary mineral associated with the oxidized zone of lead deposits.