Hackly (fracture)
It is a type of fracture which resembles a broken metal and it exhibits sharp and jagged surfaces. This type of fracture is also sometimes called "jagged" fracture.

Halides
It is a group of minerals that contain one of the halogen elements, like chlorine, fluorine, bromine, and iodine as a building block. Most of it are soft and fragile, and some are even soluble in water. Many halides even crystallize in the isometric system.

Hardness
It is the resisting characteristic of an object to scrapes and scratching. Greater resistance mean greater hardness.

Hard water
It is that type of water which is rich in calcium.

Heat treated
It is in reference to a mineral or a gem which is put under intense heat to enhance color or remove flaws.

Holocene
It is the period of geological time which is 11,500 years ago to the present day. It is the youngest epoch and series of the Cenozoic Era.

Host mineral
It is a mineral which forms the chief constituent of a particular rock.

Humic
It is a type of coal which is predominantly composed of mixed plant debris. It contains the maceral minerals. (Also see sapropelic).

Hydration
It is term used for the addition of water into the chemical structure of a mineral.

Hydrocarbons
It is an organic substances being composed of only hydrogen and carbon.

Hydrochloric acid (HCL)
It is a corrosive acid that is mainly being used for dissolving the unwanted substances. It is a destructive liquid and can destroy many minerals.

Hydrofluoric acid (HF)
It is a corrosive acid that is used for the production of glass, as it dissolves glass. It has a destructive nature and can destroy many minerals.

Hydrometallurgy
It is the treatment of ores by the wet processes. It results in the dissolution of a particular component and its subsequent recovery by precipitation, absorption or electrolysis.