Dioptase is very fragile, and specimens must be handled with great care. It is a trigonal mineral, forming 6-sided crystals that are terminated by rhombohedra.

Dioptase is an uncommon mineral found mostly in desert regions where it forms as a secondary mineral in the oxidised zone of copper sulphide mineral deposits. However, the process of its formation is not simple. The oxidation of copper sulphides should be insufficient to crystallise dioptase, as silica is normally minutely soluble in water except at highly alkaline pH. The oxidation of sulphides will generate highly acidic fluids rich in sulphuric acid that should suppress silica's solubility. However, in dry climates and with enough time, especially in areas of a mineral deposit where acids are buffered by carbonate, minute quantities of silica may react with dissolved copper forming dioptase and chrysocolla.
Ref: Wikipidia

According to Metaphysical Healers Dioptase is a stone to assist in self healing. It can help to relieve mental stress, allow for complete relaxation, and enhance the meditative state.

Dioptase can help ease the pain/hurt of grief, abandonment, betrayal, and heartache. It is an excellent stone for furthering spiritual attunement. Collectors prize dioptase for its colour.