Hatching: A technique of modeling, indicating tone and suggesting light and shade in drawing or tempera painting, using closely set parallel line.

History painting: A genre of painting that has as its subject a scene from history, a scene from mythology or a scene from great works of literature.

Hue: The perceived colour of an object identified by a common name such as red, orange, blue.

Hardness (Moh's Scale of Hardness)
The ability of a stone or mineral to resist scratching. Hardness is measured from 1-10, 10 (diamonds) being the hardest.

Heart-Shaped Cut: Stones cut in the shape of a heart.  Heart-shaped diamonds are a variation of the round brilliant-cut.

Herringbone Chain: A flexible chain that lies flat around the neck.

Hidden Clasp: A watch clasp that cannot be seen from the outside of the band.  Portions of the metal band expand out to fit over the hand and internally fold, bringing the ends of the band together for a seamless look.  Can include push buttons for added security.

Hinged Backs: Very popular in hoop earrings, this back has a hinged piece of metal that goes through the ear and snaps into a latch on the opposite side of the earring.