How Geocaching Works
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In geology, a vein is a distinct sheetlike body of crystallized minerals within a rock. This earth cache is about quartz veins in granite rock. Minerals have different hardnesses and hence different scratch resistance. This is usually reflected in the durability of the rocks where the minerals are found. A German Geologist Friedrich Mohs proposed a relative hardness scale in 1812. Mohs defined ten levels of hardness based upon 9 relatively inexpensive and common minerals:
For this earth cache only the position of feldspar and quartz are important. By definition, granite is an igneous rock with at least 20% quartz and up to 65% alkali feldspar by volume.
Granite rock with quartz veins in Idaho, United States.
Quartz can have many colours:
- Clear, colourless quartz is called rock crystal.
- Translucent white quartz is called milky quartz.
- Milky pink quartz is called rose quartz. Its colour is thought to be due to various impurities (titanium, iron, manganese) or microscopic inclusions of other minerals.
- Purple quartz is called amethyst. Its colour is due to "holes" of missing electrons in the crystal in combination with iron impurities.
- Yellow quartz is called citrine. Its colour is due to iron impurities.
- Green quartz is called prasiolite. Iron impurities account for its colour, too.
- Gray quartz is called smoky quartz. Its colour is due to "holes" of missing electrons in combination with aluminium impurities.
- Brown smoky quartz is called cairngorm and black smoky quartz is called morion.
1. Go to the place to cache coordinates point to. Write to me a few words about the quartz veins – size, colour,... How many colours can you find?
2. For inspiration look at the veins from Idaho. How are they different?
3. Does the veins on the site support Friedrich Mohs hardness scale? Why?
4. Optional: Take a picture of your GPS and view and post it with your "Found it" log. You may also be in the photo.
5. Send your answers to my profile at geocaching.com before logging online. You need not wait for my answer to log your find. I will contact you if there is a problem with your answers.
Important! Do not write the answers in the log or post photos of the quartz veins.
The veins are right next to the Pasquière Track, a nice walking track that connects the south and north side of the island. If you are lucky you can see the screw pine's enormous flowers. Also notice the traditional cache nearby Pasquière Track 2.0.
You have to have been at the location after the release date of this cache - old holiday visits do not count and are not accepted.
(No hints available.)
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Coordinates are in the WGS84 datum