Gangue
Rock and minerals that occur with ore but have no economic value.

GCNHA
Glen Canyon Natural History Association

Geoglyph
Geoglyphs were formed by ancient artists by scraping away desert pavement to reveal the lighter earth underneath. Also known as intaglios.

Geometric
A description of rock art that is abstract or non-representational.

Geyser
A geyser is a special type of hot spring that erupts periodically. Geysers are usually classified into one of two categories: fountain-type geysers generally shoot water out in various directions, most often from a pool; and, cone-type geysers erupt in a relatively narrow jet of water, usually from a cone or nozzle-like formation.

Giardia
A bacteria that contaminates water in the backcountry and can cause severe stomach cramps and other symptoms. All water should be treated before consumption while in the backcountry.

Gneiss
A coarse-grained metamorphic rock characterized by banding and parallel alignment of minerals.

Granary
A small stone structure usually built into the side of a cliff that was used for storing food.

Granite
A light-colored coarse-grained, igneous rock containing the minerals quartz and orthoclase feldspar, with lesser amounts of plagioclase feldspar, mica, and hornblende.

Grub
A heavy-bodied, immature insect, usually slow-moving, with legs on its thorax but no prolegs on its abdomen, and usually with a distinct head.

Gravel
An unconsolidated, natural accumulation of rounded rock fragments resulting from erosion, consisting predominantly of particles larger than sand, such as boulders, cobbles, pebbles, granules, or any combination of these fragments.

Gravid
Bearing eggs or developing young; pregnant.

Groundwater
Loosely, all subsurface water as distinct from surface water.

Guzzler
An artificial water development built for wildlife.