GCK9TV Mica City Earthcache
Type: Earth | Size: Not chosen | Difficulty: | Terrain:
By: geoaware @ | Hide Date: 08/16/2004 | Status: Available
Country: United States | State: Colorado
Coordinates: N39° 47.150 W105° 19.495 | Last updated: 08/30/2019 | Fav points: 21

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This Earthcache is located next to a road. The main coordinates refer to a safe place to park. Take care when visiting this site. This Earthcache come with a bonus...the opportunity to take a small mineral sample home to admire forever!

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The story.....Millions of years ago, deep within the Earth's crust, rock melted and was squeezed up into the overlying layers of rock. This molten rock material cooled slowly, forming veins of large crystals of the minerals quartz, pink feldspar, mica and other minerals. Many millions of years later, when these rocks were uplifted and exposed at he surface, geologists discovered them and named them pegmatites. In some places these can still be seen as fresh (unweathered) rock. In other places, the elements of weather and water, have reduces these just to crumbling mineral piles.In some places, these pegmatites have been mined to obtain some of their minerals.This Earthcache allows you to see two slightly different pegmatite veins.N 39 47.135 W 105 19.481Here, about half way up the road cut slope, you can find a relatively fresh pegmatite vien. It contains a number of minerals, the most obvious being the silverly mica (Muscovite). Mica is a mineral that forms in sheets, and these sheets make up a "book" of the mineral. The sheets can be easily peeled off the book and these sheets are transparent. Another mineral here is the black mineral tourmaline.N 39 47.140 W 105 19.476This site is a highly weathered pegmatite vein. The original vein has broken down to being just a pile of minerals. If you hunt around, you will find some very large mica books on the surface. Some here are almost 5 cm across.

To log this site, log in the dimensions of the largest mica book you can find and mention the number of people in your group! Also email the owner the answer to the following questions:

Both these sites are very close to each other. Why do you think that the two veins appear to be so different? (one so fresh, the other so weathered?) A possible answer is in the hint below.

11/28/2018 By chihuahuajill
Wow, what a winding road to get here! The bright sun made the minerals sparkle today! Emailed answers to CO. Thanks for placing this cache for me to find. TFTC.

10/14/2018 By Hansel and Gretal
Found awhile back. Sent info but never logged the geocache. Very interesting. Spent about 45 minutes looking at the mica. TFTC

09/24/2018 By Rock Chalk
Our Colorado vacation continued today with a drive from Golden to Grand Lake. Mostly working on the Across The Divide GeoTour, but also attempting a few other caches along the way. I came out this way this morning before we began our drive. Really enjoyed seeing the mica. Answers are on the way. TFTC!

06/28/2018 By wildkatco
It was expected to be over a hundred degrees in Denver today, so we decided to head to the high country to do some walking and caching and get out of the heat. This was one of our stops on the way to Golden Gate Canyon State Park. It's a pretty drive and we watched as the temp reading on the dash kept dropping. Yay! Found this cache and the secondary site with no difficulty. Emailed answers to CO. Thanks geoaware for placing this cache so that we can play!

10/07/2017 By drache612
Thanks for this nice earth cache, made another stop here while I was on a business trip.
Photo

03/19/2017 By LLYN-lhvwn50
Very sparkly in the sun today. Finding mica books was fun. Thanks for offering an earthcache here.

03/16/2017 By _BriGuy_
I have been planning to get this cache for awhile, and to grab the other caches on this stretch of road, and found the time this morning to do so.

Beautiful drive to the GZ. After we parked we can see the Mika real well because of the very sunny morning. It was fun looking for the books, and was pleased to learn that it does peel into sheets.

I really enjoyed this cache and appreciate the knowledge.
Mica

01/11/2017 By K Trackers
I picked up this nice earthcache up while diverting from a trip to Golden. Thanks to the CO for the informative write up and placing this nice cache for everyone to find, TFTC.
GCK9TV GZ 2

10/09/2016 By jasperdakota

Thanks for the earthcache! Nice drive to Golden Gate Canyon.
Mica

09/14/2016 By divingbrothers
Visited together wirh harrylime during our stay in the United States.

tftc

09/14/2016 By harrylime
Found with divingbrothers on our USA Tour.
Emailing answers.
Greetings from Austria!
TFTC
Photo

08/26/2016 By WalkingDuo
We gathered mica books from here with our kids 30 some years ago. My granddaughter now has my rock collection. My memory envisions much larger sheets than found today. Largest was 1 1/2 inches. I visited with my native Coloradan neighbor. The site was new for him. Thanks

07/03/2016 By GR8Caches
Day 6 of our 11 day GW14er trip. Today was about the big event we came here for. We spent most of the day on site helped out at the trackable table and stayed to see the closing. Seems we are staying to find out where the next one will be more and more. We started off the day getting the oldest active earth cache (in the US?) before heading to the event. We headed south at the end of the day leaving Denver behind. We started nearer the cords but before leaving we found the honey hole. Neat cache and enjoyed grabbing it. I don't know for sure if this is the oldest EC or the oldest in the US? There is one in NC that is older but it started out as a traditional cache and became an EC so not sure how that comes into play with this one. I am calling it the oldest in the US for my stats....on this trip until I learn different. Answers on the way.

This was our summer vacation out west. We added 2 new states to our caching map (CO-NM), leaving us with just 2 more states to find. One of the caching highlights was finding the Oldest Active; Traditional Cache (Mingo), Letter Box Hybrid (Open Space 6) and Earth Cache (Mica City Earthcache). We seeked out lots of favorite caches and even added some over 14k feet high caches to our finds.

Grcaches is a husband/wife team that lives near Harpers Ferry WV, we started caching in March of 2006 this year marks our 10th anniversary of caching. It is hard to believe we have now been caching that long. We have enjoyed our 10 years so much that our goal is to find all the rest of the caches we haven't found in the next 10 years. A big THANKS goes to geoaware for placing this gr cache! This was our 17819 find.

Mica