This cache has been archived.

Inuksuuk: If you Google "public boat launch Jack Lake Apsley" you can find out about the public outcry from locals regarding the Town Council's decision to sell the public property for commercial use. Cottagers and local residents have a Facebook page dedicated to the fight to preserve this public boat launch but Council has a lawyer and seems to have won. The only other boat access is a Marina in the far north end of the lake which is just not feasible for canoes and kayaks coming to this Earthcache. Therefore we have decided to archive both of our Earthcaches, sadly, and to keep ears and eyes attuned to any developments on the issues. It seems our canoeing days on beautiful Jack Lake have come to a tragic end. Very unfortunate it is for geocachers, as the D/T rating on this EC was rare and highly sought after.

GC6K2DJ ▼

A cache by Inuksuk & Terryer Message this owner

Hidden : 6/3/2016

Difficulty:

Terrain:

Size: Size: other (other)

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Geocache Description:

This is a water access only Earthcache. You will need a boat.

KalSi308 (Feldspar)

(I thought of just calling this Earthcache, "Orthoclase Potassium Aluminum Silicate Feldspar" but KalSi308 seemed a little easier)

Requirements for Logging :

Take a kayak or canoe over to the granite island, look for cube-like crystals of feldspar partially embedded in the base rock and answer the following questions. Email your answers to the CO.

1. Find a cube-like crystal of feldspar. Use your fingers to touch it, counting the number of flat faces and pointed vertices. For example, is there only one side (face) showing, or 2 sides, perhaps 3 or even 4 ? Also count the number of vertices (corners) exposed. How many vertices?

2. Are any of the sides of your feldspar sample forming 90 degree angles at their vertex?

3. Describe the luster, colour, and texture of the feldspar. For example is it vitreous, light pink, and smooth? or pearly, deep red, and rough?

What mineral makes up as much as 60% of the Earth's crust ?

Why, feldspars, of course !! Everyone's heard of feldspar !

Not everyone? Okay.... but everyone has heard of granite? Granite is an igneous rock comprised of three main minerals : quartz, mica, and .... you guessed it, feldspar ! In fact, granite is 50-70% alkaline feldspar.

The term feldspar ("field mineral") is more important to you than you may think. Feldspars are used as aggregate in concrete and asphalt. They are also used as fluxing agents in ceramics and glass, and are used as fillers in paint, plastic, rubber and adhesives. In fact, most of the products we use on a daily basis are made with feldspar: glass for drinking, fiberglass for insulation, the floor tiles and shower basins in our bathrooms, and the tableware from which we eat. Feldspar is part of our daily life.

Feldspars are a group of silicate minerals that can be found in all three major types of rock : igneous, metamorphic and sedimentary. Feldspar is subdivided into Orthoclase (KalSi3O8), Albite (NaAlSi3O8) and Anorthite (CaAl2Si2O8). Chemically, the feldspars are silicates of aluminium, containing sodium, potassium, iron, calcium, and barium or combinations of these elements. Feldspars crystallize from magma in monoclinic and triclinic forms. This basically has to do with whether or not there are any 90 degree angles in the crystal shapes which may cause them to appear "squarish and cube-like" or appear more irregular. Crystallography is a complicated science, and you could spend hours reading about the 7 formations of crystals and their subcategories, but for the purposes of this Earthcache, you only need to understand that, although feldspar does not form perfect cubic crystals as do some of the metallic minerals such as pyrite, orthoclase feldspar is characterized by the presence of 2 planes of cleavage that meet at one 90 degree angle so that the cubes of feldspar appear to have flat sides (faces) and pointed vertices (corners).

Feldspar is mined from large granite bodies (called plutons by geologists), as well as from pegmatites (formed when the last fluid stages of a crystallizing granite becomes concentrated in small liquid and vapor-rich pockets that allow the growth of extremely large crystals), and from sands composed mostly of feldspar.

The minerals of which the composition is comprised between Albite and Anorthite are known as the plagioclase feldspars, while those comprised between Albite and Orthoclase are called the alkali feldspars due to the presence of alkali metals sodium and potassium.

Orthoclase feldspar comes from the Greek "orthos" which means "right" and "kalo" which means "I cleave" because the mineral has good cleavage at a right angle. Orthoclase is polymorphous with the minerals Microcline and Sanidine. These three minerals form the Potassium Feldspar group. They are almost identical in physical properties, and it is sometimes impossible to distinguish one another without x-ray analysis. The only difference between them is their crystal structure. Microcline crystallizes in the triclinic system, and Orthoclase and Sanidine crystallize in the monoclinic system. Sanidine forms at high temperatures and has a disordered monoclinic symmetry, whereas Orthoclase forms at low temperatures and cools slowly, forming more ordered monoclinic crystals. In some mineral reference guides, Microcline and Sanidine are wrongly categorized as variety of Orthoclase. Since it is so difficult to distinguish between Orthoclase, Sanidine, and Microcline, they may be simply called "Potassium Feldspar".

See more at: http://www.minerals.net/mineral/orthoclase.aspx#sthash.LN8hSmbN.dpuf

At this website you can click on each crystal formation and watch it in 3-D !!

http://www.minerals.net/mineral/orthoclase.aspx