Rock Solid

Armed with picks, shovels and hammers, they venture out to traverse dry, desert trails, seldom-used mountain paths and abandoned mine dumps in search of treasure. They spend hours, and often days, in their quest. And when their journeys are over, they return home with their prizes: rocks.

Scouring dry lakes and dusty deserts for rocks may not seem like the most exciting way to spend a free afternoon, but for avid rock hounds, few activities can compare.

The quest for gems and minerals, collectors say, is addicting. The excitement is in the thrill of the hunt, finding the rocks that hold gems and minerals among the endless supply of similar-looking worthless rocks.

That hunt generally requires a journey out of the city. About all the San Fernando Valley has to offer is fossils, which are found in isolated areas including Old Topanga Canyon Road.

The vast Mojave Desert, on the other hand, is rich in gems and minerals, including howlite, garnet and travertine.

Getting Into a Rock Hounding

Joining a gem and mineral club gives novices the chance to learn from experienced collectors who say some rocks are easily passed over by untrained eyes. Some clubs also have lapidary equipment available for members to use.

Southland clubs include:

Woodland Hills Rock Chippers (818) 347-2056

Del Air Rockhounds Club (818) 883-7851

VIP Gem and Mineral Society (818) 996-1630

Sierra Pelona Rock Club (805) 296-2299

Antelope Valley Gem and Mineral Club (805) 943-5157

Palmdale Gem and Mineral Club (805) 947-1306

Valley Gems (805) 942-1570

Mineralogical Society of Southern California (818) 286-2915

Researched by Sharon Moeser/For The Times

* Collecting mineral and rock specimens is a hobby that dates back to the 19th century. Collectors use their finds for everything from landscape accents to tabletops, bookends and jewelry.

A Collection of Rocks

Precious opal

* Identifying features: Rainbow-colored gemstone is milky-white or black withrich internal play of color (opalescence) which can change as a result of warming of water in the mineral. Name is from Sanskrit upala, meaning ‘precious stone.’

* How it forms: Made up of silicon and oxygen, forms in silica-rich water, especially around hot springs. Usually develops in a variety of rocks as cavity and fracture filling.

* Where found locally: North of Mojave there are a pair of private opal mines that are open for a fee to the public.

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Jasper

* Identifying features: Dark red type of chalcedony quartz mineral made of small fibers or rods. Its opaque reddish brown color indicates iron oxide.

* How it forms: Forms in cavities and fractures of various rocks, particularly lavas.

* Where found locally: Readily found, including sites in the Antelope Valley.

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Agate

* Identifying features: Fine-grained type of quartz with bands of colors ranging from whiteto gray to black. Colors result from impurities such as iron oxide and manganese oxide.

* How formed: Agate is a type of silica, which is formed from silicon and oxygen. The sand on beaches is powdered silica, which was formed by rocks broken up by weathering.

* Where found locally: Usually Northern California beaches. Locally, the community of Acton has a type which is clear or blue with white bands and a red outer shell.

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Rhodonite

* Identifying features: Pink to red to brownish mineral, often with black veins of manganese. Often used as an ornamental stone and gemstone. Name is from the Greek rhodon, meaning rose, in reference to the mineral’s color.

* How formed: Forms in metamorphic rocks rich in manganese.

* Where found locally: South Antelope Valley, particularly along the Ritter Ridge.

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Tools to Take Along

A beginner can start collecting rocks with little more than a rock pick and shovel. Shown here are commonly used tools:

Goggles: Protects eyes from bits of rock flying off of area being hammered.

Pick hammer: Geologists’ type has a hammer on one end and a pick on the other.

Chisel: Used to pry minerals out of rock.

Safety helmet: Worn to protect skull. Even small falling rock fragments can cause injury.

Gloves: Made of heavy canvas or leather to protect hands when handling rocks.

Sources: he Complete Book of Rocks and Minerals; Eyewitness Books Rocks and Minerals; National Audubon Society Field Guide to North American Rocks and Minerals; Tony Kampf, Los Angeles County Natural History Museum; Jim Schlegel, Mineralogical Society of Southern California; rock hounds Jules Ficke, Ken Ronney and Bob Backus. Researched by SHARON MOESER/For The Times; Sources: Tony Kampf, curator of minerals and gems, Los Angeles County Natural History Museum; Jim Schlegel, field trip chairman, Mineralogical Society of Southern California; area rock hounds Jules Ficke, Ken Ronney and Bob Backus.