Rockhound Geocaching

Filed under: Rockhound Travel,rockhounding maps — Gary June 25, 2010 @ 9:07 pm

Geocaching is fun, educational and can be enjoyed by the whole family!  What is geocaching you say???

What is Geocaching?
Geocaching is a worldwide game of hiding and seeking treasure. A geocacher can place a geocache in the world, pinpoint its location using GPS technology and then share the geocache’s existence and location online. Anyone with a GPS unit can then try to locate the geocache.
How do you pronounce Geocaching?
You pronounce it Geo-cashing, like cashing a check.
What is the meaning of the word Geocaching?
The word Geocaching refers to GEO for geography, and to CACHING, the process of hiding a cache. A cache in computer terms is information usually stored in memory to make it faster to retrieve, but the term is also used in hiking/camping as a hiding place for concealing and preserving provisions.

Only three rules:

1. If you take something from the cache, leave something of equal or greater value.
2. Write about your find in the cache logbook.
3. Log your experience at

There are finds all around the world that have rockhounding treasures just waiting to be found.  You can search the caches by “keywords”.  I have listed a couple below BUT there are many more out there.  If you make your own rockhound cache please send me an email so I can post for everyone.

Click here for list of mineral caches (below are a couple in detail)

Rocks/Minerals at Black Star Canyon

Black Star Canyon

Black Star Canyon

The Irvine Ranch Conservancy was established in 2005. It is a non-profit, non-advocacy organization, created to help care for the 50,000 acres of permanently protected wildlands and parks on the historic Irvine Ranch. The organization works with its partners to enhance the public’s appreciation, understanding and connection to the land, while helping other land owners and managers with all aspects of stewardship. The Conservancy contributes its resources, expertise and energy to achieve the best possible balance of preservation and public participation.Nearly 40,000 acres of the 50,000 acres indicated above of open space on the historic Irvine Ranch have been designated a Natural Landmark by both the State of California and the U.S. Department of Interior. This honor recognizes the exceptional value of these lands to California and the entire nation.

Beautiful geological formations – including “the Sinks”, “Dripping Springs” and the rock formations located at Black Star Canyon – plus a rich diversity of flora and fauna make the The Irvine Ranch a favorite among hikers, mountain bikers and naturalists.

This cache is placed with the permission from and in cooperation with the Irvine Ranch Conservancy. Access is limited; reservations for docent-led outings are required due to the area’s sensitive habitat. Pre-registration is required for all programs. No walk-up registration is allowed, no exceptions. Registration for weekday programs closes at 4 p.m. on the day prior to the event and registration for weekend programs closes at 4 p.m. on the Friday prior to the event. A calendar of scheduled hikes can be found at Additionally, they can be reached at (714) 508-4757 to coordinate small or large group hikes for these Earthcaches and other hikes within the Conservancy boundaries.

Santiago Canyon embodies the romance and lore of Orange County’s colorful history: The canyon’s past is punctuated by coal-mining operations, grizzly bear hunts, manhunts and homesteaders. The canyon was a major thoroughfare for early settlers who settled in its scenic side canyons-Baker, Black Star, Silverado and Modjeska. Traces of Orange County’s earliest residents were discovered at Black Star Canyon. Arrowheads and rocks pockmarked with grinder holes (signs that the Indians ground acorns to produce an edible gruel) have been found on the plateau high above the canyon, where a large Indian village once existed. Black Star Canyon got its name in the 1870’s, when Black Star Mining Company began mining for coal that recently had been discovered there. The mining operation was short-lived, though, because the quality of the coal was so poor.

This cache is designed for kids, but can be enjoyed by all cachers.

Color can be used to help determine specific minerals in a rock. While this has been determined to be one of the least effective methods in identifying rock/mineral content, it does provide a starting place when including or eliminating mineral content from rock formations. The below are some examples of mineral and rock colors and related minerals/rocks:

Light Grey or Tan–Sandstone is a sedimentary rock composed mainly of sand-size mineral or rock grains. Sand and the sandstone it creates can be an color (the sandstone would be reflective of the color of the base sand in its formation. Since sandstone beds often form highly visible cliffs and other topographic features, certain colors of sandstone have been strongly identified with certain regions. Colors will usually be light grey or tan. Sandstone has been a main building material dating back into most of history.

Red – Iron Oxide: When air touches iron materials over a long period of time the process will “rust” (oxidize) the iron minerals in the sediment to give a reddish color to the rocks. Based upon the type of base rock, and the amount of iron materials in the formation, the color of red will vary from very dark as seen below, to lighter pinks. Iron Oxide has historically been used as the basis for several paint colors including Burnt Sienna, Burnt Umber, Chestnut, Sienna, Venetian Red and Mummy Brown.

Dark Grey – Siltstone: Silt is a size term used for material that is smaller than sand but larger than clay. Siltstone is defined as having twice as much silt as clay.

Blue – Azurite: Azurite is a soft, deep blue copper mineral produced by weathering of copper ore deposits.

Yellow – Sulfur: Sulfur in its native form is a yellow crystal. Common uses are primarily found in fertilizers, matches, insecticides and fungicides.

Green – Epidote: The color is green, grey, brown or nearly black, but usually a characteristic shade of yellowish-green or pistachio-green.

Metallic Gold – Pyrite: Its metallic luster and pale-to-normal gold-yellow hue have earned it the nickname fool’s gold, but ironically enough, small quantities of actual gold can sometimes be found in pyrite. This is primarily sold in retail shops as it appears to be gold, but also had been used in old-time radios.

Metallic Grey – Mica: Mica is a flaky grey mineral that provides for a metallic look when seen with several layers together. Mica is used in stoves and lanterns as it is somewhat clear, but is heat resistant. Mica can also be found in paint, wallpaper, roof paper, cosmetics and insulators, as well as other common applications.
In order to log this cache, from the coordinates, you will need to identify three rock/mineral types provided above. Please face west and look both at the formations at approximately 315 degrees and then at approximately 225 degrees.

1. At 315 degrees, you should see two different and distinct colors in the rock formations. Email me (logs that provide the answer will be deleted) both colors, and based upon the above what type of rock or mineral content you think both individually contain.
2. At 225 degrees, about 1/3 up from the bottom of the formation, there is a different color of rocks compared to the rock and/or mineral identified in #1 above. Email me (logs that provide the answer will be deleted) what color this formation is, and based upon the above what type of rock you think it is.
3. Based upon the colors discovered, email me (logs that provide the answer will be deleted) which mineral do you see the most of.
4. Also, post a picture with you, your group and your GPS from the coordinates with the formation in background.

(actual webpage of this info- click here-)


Mining, minerals, & marshes in the Duddon Estuary

quartz vein

quartz vein

The Duddon Estuary is a landscape shaped by geological forces, glaciers, then finally, man, here at Hodbarrow you will see evidence of both, rock formations dating back millions of years and a 19th century unusual lagoon formed for heamatite iron mining.
With the Lakeland fells behind, the Duddon estuary presents an ever changing view, the bedrock was laid odwn millions of years ago, when the Holcene glaciers retreated, melting 10,000 years ago, they left behind thick layers of sediment, powerful ocean tides have then sculpted a scene of mudflats,dunes, water and salt marshes which run right along the coast towards Broughton in Furness, the salt marsh landscape is thought to look as it would have 10,000 years ago.
limestone pavement

limestone pavement

At the coordinates given for the cache, you will find your self on a small remote beach looking out into the bay, the rock that you will be standing on and that is all around you is Carboniferous limestone, but what is that exactly ?

Carboniferous limestone is a sedimentary rock made of calcium carbonate. It is usually light-grey in colour, and is hard, gripy when dry but slippery when wet. It was formed in warm, shallow tropical seas teeming with life. The rock is made up of the shells and hard parts of millions of sea creatures, encased in carbonate mud. Fossil corals, brachiopods and crinoids are very much in evidence as components of Carboniferous limestone.

This limestone area of the beach that leads into the sea has charachteristics of a limestone pavement hoever is has been eroded by the sea and now has many unusual shapes which now form rock pools whereas more inland these ‘grikes’ more than likely would house a habitat of their own, which encourages the growth of shade-loving ferns and other fauna.

Interestingly the limestone here also contains quartz, it can be seen as veins running through the rock and also clusters of it protruding through the limestone on various parts of the beach, Quartz is an essential constituent of granite and other felsic igneous rocks. It is very common in sedimentary rocks such as sandstone and shale and is also present in variable amounts as an accessory mineral in most carbonate rocks. Quartz wasn’t the only thing to have been discovered in Hodbarrow though… in the 18th century high grade Haematite ores with an iron content on 40% – 62% were discovered and that led to Hodbarrow going from a quiet area to a mining giant

The Hodbarrow Iron mine
The Hodbarrow mine evolved to become one the most productive and important haematite mines in the world, iron ore mining began in 1880 and with it came the start of an epic battle with the sea, after 2 unsucessful attempts to sheild the mines from the sea by using barriers a huge engineering project was started to build what is now known as the ‘Hobarrow outer wall’ this wall creating the ‘lagoon’ you see here today cost £600,000, took five years to build and when it was finished in 1905 it was considered to be a work of unusual and exceptional kind.
The mines closed in 1968 but the barrier still stands as a poignant reminder of the industrial past, the are has now been reclaimed by nature and is now a reserve for wildlife including the increasingly rare Natterjack toad

You will have to visit three locations to complete the tasks, all showing you different things relating to this cache, the locations are close together and you can pick up some traditional caches en route

To claim this Earthcache please complete the following tasks:

1. At the given coordinates for the cache take a photo of you or your GPS on the Limestone beach.

2. At the same place identify and take a photo of an example of quartz coming through the limestone, please describe the colour of the quartz you discover

3. At 54.11.571 003.15.382 you will see an information board, what is being tipped at Millom in the picture on the left ?

4.At 54.11.417 003.16.039 you will be stood on the sea barrier by the large lighthouse, there is an information board, what happened in 1924?

Please post your photo’s in your log and email the answers to me directly, any logs without this information may be deleted

Have fun exploring this fantastic area

actual website location– click here-

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