Agate hunting is a rewarding, meditative, cost effective activity suitable for girlfriends, couples and families. Agates make beautiful jewelry and awesome home decor accents. Below, Dr. Karen E. Bledsoe beaks down the basics of this classic beach coming pastime. Article excerpts via helium.com.
What: 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: 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.
- 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.
- Cloud agates, also called blue agates, are mottled with blue-black, blue, and milky colors. True blue agates are highly prized.
- Moss agates don’t really have moss in them. Mineral deposits form the branched, mossy patterns seen in these stones. Many form tree-like pictures, and are called landscape agates.
- Jasper is another massy quartz stone found alongside agates. It is not transparent, but is often brilliantly colored. Jasper comes in red, yellow, and green.
- Bloodstone is a type of dark green jasper with red spots. It is fairly rare. Bloodstone is sometimes called Heliotrope.
- Petrified wood is formed when agate or jasper deposits replace wood. It is a type of fossil.
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