In The Desert
Content including photographs are Copyright © 2014 - Present - Don & Linda Gilmore
We'll start off with minerals and rocks that are common finds in the desert (unless noted otherwise). Some are utilized in jewelry. Don't miss the Fluorescence Link!
There are a lot of minerals and rocks in the desert southwest. We've just published some of the more common ones that you might come across to help you identify them. Have any you'd like to share?
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Just a short 10 years ago who would have guessed that you could find 2 little nuggets like this and that they'd be worth $102 dollars? Digging these out took at least a half hours work. The metal detector to do this (a Minelab) cost over $3,000. But you might just be able to pay it off and then make a profit.
These 3 little nuggets were dry panned at an old mining site near Yuma, Arizona. Value, over $180 dollars. Time involved, just over 3 hours. Plastic gold pan and shovel cost about $22. Does this mean you can go and get lucky? You never know, but these minerals are something to keep an eye out for.
Often found in small clusters as shown here. These are not worth anything except as a collectors item. There is a whole family of different looking crystals that are in the quartz family, a lot of them have different color variations.
This is another form of quartz often erroneously called a Desert Rose. Desert Rose's are red in color. This is a nice example of Chalcedony. This photo was taken near Yuma, AZ.
It's very unlikely that you will find silver ore in the desert. You may look right at it and not know what your looking at. If it is exposed it will probably be almost black in color from oxidation. If you own any real silver (dinnerware or jewelry) you'll know this when you have to polish it. There are very few locations in the desert southwest or Mexico where raw chunks were found and you could tell what they were just by looking at them. Any additional information about this would be appreciated.
This is one of the least sought after minerals. And it can be found in many locations in the desert southwest. Usually found in the Blue/Green form known as Chrysocolla. Many people mistake this for Turquoise. But if you look at the Turquoise sample below you'll see the difference in matrix and color. Here's a couple common examples of Copper ore.
This is the way Chrysocolla is usually found in a matrix of other rocks. People like to collect them because of the coloration and a mistaken identity.
The sample to the right is the same ore but much richer. If an area of this ore could be found then you might be able to sell the location to a big mining company. This is a very rich sample and quite big. Raw Native Copper is not usually found, but can demand a decent price. See small insert above.
Not often found, although we have found sheets of gypsum just north of Wellton, Arizona in a layer of red dirt. They were as pictured here, almost clear, and you could see through them. This mineral is also called selenite.
Unless you can find some really nice specimens like the ones to the right, you'll just want to keep them for a keepsake item. Larger ones like this can demand a good price.
Amethyst crystals are often found inside a vug in a geode. They can also be found in quartz veins. Not a common find in the desert. Also in the quartz family.
Highly prized by the Native American Indians and the Mayans. Thousands of jewelry pieces are in existence today. Many mines still exist just for mining this material. It can still be found in some mine dump areas. Finding a good vein of turquoise could be worth some money.
This is called a watermelon tourmaline because of the red to greenish coloration. This is a boron silicate mineral. It is also a semi-precious stone. Aluminium, iron, magnesium, sodium, lithium and potassium may be found in this gem in varying amounts. The above minerals vary it color. This one was found in a mine in southern California.
Only found in a few places in the world with one of the best mining areas just north of Yuma, Arizona at the Red Cloud mine. This sample was given to us by the caretaker at the mine. You can still find nice crystal specimens on the tailings piles at that mine and others close by.
Usually founds in two different forms in the desert. As pieces like this one shown here, which were often worked into arrow points, knives, and fleshers by earlier generations of people living here. And in another form often called Apache Tears. which is the same material that has been weathered by wind, sand, and water into roundish balls of this black material. It can have very sharp edges.
Often found as petrified wood. In some cases it can be very valuable. These sample came from New Mexico but can be found all over in the desert southwest. These sample photos were given to us by Betty Reid Martin. The top photo is what is considered "banded" agate. There are a lot of different color variations associated with agate. We've found many pieces of green agate in the desert north of Wellton, AZ. Other colors also exist.
Often found in panning and sluicing for gold as small flakes mixed in with the black sand. Called "Fools Gold" by the early miners. Shown here is a sample of Pyrite Crystals found in a mine near the south side of the Grand Canyon.
Often found in panning and sluicing for gold as red stones. We found many of these small crystals while dredging in rivers in CA. Also found in mines and tailings piles of mines throughout the southwest. We've even found them on the Barry Goldwater Bombing Range near Yuma, AZ embedded in slabs of Mica. Most are red or green in color.
Sometimes found as big slabs and in the early 1900's this would have been worth some money as it was used in windows or wood stoves and clothes irons. This sample has small inclusions of garnet. Several nice gem quality garnets were found in this mica.
At times magnetite will look like any of the other stones found in the area. The best way to tell if it is magnetite is by testing with a magnet.
California Serpentine has a flaky look and all serpentine minerals have a green waxy look to them. Some are hard enough to shape and polish into nice specimens, but care needs to be taken working with material as it is the primary source of asbestos and breathing the dust is very unhealthy.
It's color is usually what gives it away. Prospectors looking for uranium looked for yellow colored rocks and Prince's Plume (wildflower) was another sign. It grows in areas were you find selenium which is usually near Uranium. Of course a geiger counter is another way. Use extreme care when handling these samples.
This is Calcite in Chalcedony. Photo was taken in the Humbolt Sink just south of Lovelock, Nevada.
Photo courtesy of Stephen D. Zepeda
Photo courtesy of John Mathias
How to Identify Rocks
Identifying rocks can be quite a chore and at times it's just guess work on your part. You can ask on social media, but are you going to get the correct answer? Here's a chart that will help to identify the 3 basic types of rocks with information about how they were formed and what they are made from. This is a very interesting chart! Open the enlargement and view full size.
Halite, Rock Salt
Halite is the mineral name for the substance that everyone knows as "salt". Its chemical name is "sodium chloride", and a rock composed primarily of halite is known as "rock salt". It can be white or also pink.
Photo courtesy of John Mathias
Also Calcite, photo by Greg Watson - It's fluorescent under a UV light
It's a calcium tungstate (a type of tungsten ore) mineral with the chemical formula CaWO4. It is an important ore of tungsten (wolfram). Well-formed crystals are sought by collectors and are occasionally fashioned into gemstones when suitably free of flaws. Unkknown matrix, view under a UV to see what part of this is Scheelite.
Opal is a hydrated amorphous form of silica (SiO2-nH2O); its water content may range from 3 to 21% by weight, but is usually between 6 and 10%. Because of its amorphous character, it is classed as a mineraloid, unlike crystalline forms of silica, which are classed as minerals. It is deposited at a relatively low temperature and may occur in the fissures of almost any kind of rock, being most commonly found with limonite, sandstone, rhyolite, marl, and basalt.
Photo courtesy of Greg Watson
Photo courtesy of Greg Watson
What do some of these rocks, minerals look like under a UV lilght ---