Descriptionary

ford a shallow portion of a river allowing people to cross on foot.

fork portion of a river that branches into two parts.

freshet an overflow of a stream due to heavy rains or melting snow.

gradient the rate of descent over a section of river, usually measured in feet per mile.

haystacks the large, standing waves that form at the bottom of rapids wherever the current is decelerating.

headwaters small brooks and streams that join to form a river.

hummock a flow of current forming a hump over a rock.

hydraulics the science of water in motion.

hydrologist one who studies the dynamics of water. hydrophobia the fear of water. kill a creek.

levee an embankment built along the shore of a river to protect from flooding.

meander to wind or wander aimlessly, as a river.

milldam a dam constructed across a river to raise its water level and pressure in order to turn a mill wheel.

millrace the river or channel of water used to turn a mill wheel.

moraine a huge deposit of boulders, gravel, and silt left behind by a receding glacier and responsible for damming up some rivers to form lakes.

oxbow a noose-shaped loop of water forming along the side of a river, sometimes separating from the river entirely to form a pond.

pitch a section of rapids that is steeper than sur­rounding sections.

pool slow-moving deep water.

race a portion of a river that is moving swiftly, espe­cially due to a narrowing.

rapids swiftly moving white water broken by rocks.

riffles a shallow stream with small ripples caused by a bed of cobbles, rocks, and gravel.

rill a tiny stream or brook.

rip a wave or waves caused by a collision of cur­rents in swiftly moving water.

riparian referring to a riverbank area.

riverhead a river's source.

rooster a standing wave with a crest that turns back on itself, sometimes known to swamp canoes or rafts.

runnel a tiny brook or stream.

runoff water from rain or melted snow coursing over the ground or through sewers into a waterway.

shoal a shallow area surrounded by deeper water.

sluice an artificial channel for conducting water.

souse hole a foamy, violently turbulent eddy; also known as a white eddy.

spring a water source issuing from underground.

Styx the river of hate, one of the five rivers in Greek mythology surrounding Hades.

tongue a smooth passage of black water flowing between two rocks or obstructions, often leading into a chute.

torrent a rough and swiftly flowing stream.

tributary a stream or river that "contributes" its water to a larger river or body of water.

vortex a whirlpool.

watershed the area from which a river receives its water.

whirlpool water pulled by current forces into a rotating motion that exerts a powerful draw on sur­rounding water or debris.

white water rapids.

rocks and gems

acroite a colorless variety of tourmaline.

adularescent having a lustrous, bluish-white hue, as a moonstone.

adularia a variety of moonstone, characterized by a semitranslucent and whiteish-blue hue.

agate a type of porous quartz that forms several dif­ferent colors.

agglomerate a pyroclastic rock consisting mostly of volcanic bombs.

alexandrite a variety of quartz that appears blue- green when viewed outside and reddish-purple under indoor or artificial light.

alluvium sand, mud, gravel, and rocks carried and deposited by rivers.

almandine a type of common garnet characterized by colors ranging from red or purplish red to orange- brown.

amber yellowish, translucent fossilized resin from coniferous trees.

American ruby a ruby in name only, actually a pyrope garnet.

amethyst a type of purple or sometimes mauve- colored quartz.

ametrine a type of quartz containing both amethyst and citrine colors.

ammolite the shell of an ammonite, an ancient sea mollusk, that has been pressurized, fossilized, and mineralized.

amygdule a cavity in igneous rock filled with sec­ondary minerals, such as calcite or quartz.

anthracite a hard, lustrous, jet-black coal formed from prehistoric plant material.

anticline a folded mass of rock with strata sloping down on both sides from a common peak.

aquamarine a variety of beryl, blue or turquoise, the color often reminiscent of seawater. It is also found in yellows, pinks, and whites.

aquifer fractured rocks or unconsolidated sand or gravel pockets containing large amounts of ground- water.

asterism a starburst effect seen in such gemstones as garnets, sapphires, and rubies.

aventurescence a kind of sparkle seen in some gem- stones, due to trace deposits of mica, hematite, or pyrite.

azurite a copper-based mineral characterized by a pale to deep blue color.

baffa diamond a fake diamond, actually made of rock crystal.