by Karen Bledsoe

Created on: March 17, 2008   Last Updated: March 19, 2008

"Child finds precious stone in bucket of gravel!"

Maybe you've seen headlines like that and wished you could find gemstones yourself. There is one kind you can find easily, if you know where to look. Finding semi-precious agates may never make you rich, but agate-hunting can be a rewarding and colorful hobby.

WHAT AGATES ARE
Agates are transparent stones made up of quartz and a number of colored minerals. Silica - the same mineral that sand and computer chips are made of - dissolved in water creeps into small spaces in volcanic rock. When the silica is left behind it crystallizes. Slow crystallization results in large crystals that are valuable as gems: amethyst, rose quartz, and rock crystal are examples. Fast crystallization forms "massy," glass-like quartz such as agate, jasper, tiger-eye, aventurine, and onyx.

HOW TO FIND AGATES
Deposits of agate are usually found in igneous rock and are washed free by water erosion. Any place where rivers, streams, or the ocean wear away at volcanic rock you can often find agates: pebble-strewn beaches, gravel beds along rivers, rocky stream bottoms. Rocky shores where seashell hunting is a disappointment will often yield agates instead.

Patience is the key in agate hunting. Most hunters stroll slowly through patches of gravel, watching for a flash of color among the rocks. In strong sunlight, the clear agates will stand out against darker rocks. Hunting among wet pebbles is usually more productive, since wetness makes the colors brighter and the clear stones more obvious. On the beach, outgoing tides reveal freshly-churned gravel beds ready to be picked over.

Agate grounds along the west coast are often unpredictable, yielding a rich supply one year and none the next. Local rock shops will usually be happy to tell you where to look. For safety's sake, never turn your back on the sea. "Sneaker" waves can be extremely dangerous. Do not be tempted to climb cliffs and bluffs in search of agate veins. Climbing ocean cliffs is dangerous, environmentally unsound, and may involve trespassing.

TYPES OF AGATES
Carnelians are most common. They are transparent stones which may be rich orange-red, yellow, white, or brown, with little or no banding. The lightest forms are called Sard.

Moonstones are bright, milky white, clear stones. Moonstones with rainbows in them are called iris agates.

Ribbon agate has straight bands of color caused by different mineral impurities as the silica was deposited. If the bands are wavy, the stone is called fortification

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