This EarthCache takes you to Albert Close in Perth, more specifically to look at a remanant of the old medieval wall that once surrounded Perth. You need to walk down Albert Close. We are looking for a spotty stone in the wall. It is garnett schist. Though we are not here to discuss schist, we are here to look at the garnets.
We are here to look for something called a Garnet.
So what are Garnets, well they are a crystal, which can be red, brown, yellow, black or green. It is formed from silicate mineral. Garnets are found in highly metamorphased rocks and some igneous rocks. They are a a stone of great beauty and moderate economic value. Often a deep translucent or transparent red, garnet is a popular gem. One type of garnet is also used to produce commercial abrasives such as sandpaper and polishing grit.
There are Six varieties of garnets (and there are many gradations between them), they occur fairly frequently in deposits scattered about the world.
Almandine, is the most common of all garnets, is usually deep red to reddish brown and sometimes purplish. Due to its large iron content, it is paramagnetic (attracted to a magnet).
Pyrope, is less widely distributed but more valuable as a gemstone, is rose-red to reddish purple in colour.
Grossular garnets are yellow to brownish hue crystals typically found in contact with limestone or marble metamorphic rocks. These garnets are rich in calcium.
Spessartite garnets are a yellowy and orange colour, due to the prescene of magnesium in the stone.
Uvarovite garnets have a green colour.
Andradite garnets consist mainly of iron, however due to the iron being contained in different structures in the garnet, so at times some andradite garnets sometimes can emit a diamond or yellowish colour.
This is meant to be a simple EarthCache, that allows you to see something you may not often see.
This being an EarthCache, in order to log it, I ask that you answer the above questions. Please send them to me, and do not include them in your log. You can send them to me by using the message facility or email, both of which can be found by looking at my profile.
1. Look at the garnets, what are their diameter?
2. Using the above information, what type of garnet do you think we have here? Please describe the Garnetts and explain the rationale for your answer.