First: The junior high chemistry lesson:
Although it is the eighth most abundant element in the universe and
the seventh most abundant element in the earth's crust, magnesium
is never found free in nature. Magnesium was first isolated by Sir
Humphry Davy, an English chemist, through the electrolysis of a
mixture of magnesium oxide (MgO) and mercuric oxide (HgO) in 1808.
Today, magnesium can be extracted from the minerals dolomite
(CaCO3·MgCO3) and carnallite (KCl·MgCl2·6H2O), but is most often
obtained from seawater. Every cubic kilometer of seawater contains
about 1.3 billion kilograms of magnesium (12 billion pounds per
cubic mile).
Magnesium burns with a brilliant white light and is used in
pyrotechnics, flares and photographic flashbulbs. Magnesium is the
lightest metal that can be used to build things, although its use
as a structural material is limited since it burns at relatively
low temperatures. Magnesium is frequently alloyed with aluminum,
which makes aluminum easier to roll, extrude and weld.
Magnesium-aluminum alloys are used where strong, lightweight
materials are required, such as in airplanes, missiles and rockets.
Cameras, horseshoes, baseball catchers' masks and snowshoes are
other items that are made from magnesium alloys.
Magnesium oxide (MgO), also known as magnesia, is the second most
abundant compound in the earth's crust. Magnesium oxide is used in
some antacids, in making crucibles and insulating materials, in
refining some metals from their ores and in some types of cements.
When combined with water (H2O), magnesia forms magnesium hydroxide
(Mg(OH)2), better known as milk of magnesia, which is commonly used
as an antacid and as a laxative.
Hydrated magnesium sulphate (MgSO4·7H2O), better known as Epsom
salt, was discovered in 1618 by a farmer in Epsom, England, when
his cows refused to drink the water from a certain mineral well. He
tasted the water and found that it tasted very bitter. He also
noticed that it helped heal scratches and rashes on his skin. Epsom
salt is still used today to treat minor skin abrasions.
Other magnesium compounds include magnesium carbonate (MgCO3) and
magnesium fluoride (MgF2). Magnesium carbonate is used to make some
types of paints and inks and is added to table salt to prevent
caking. A thin film of magnesium fluoride is applied to optical
lenses to help reduce glare and reflections.
Some minerals containing Magnesium include:
Polycrystalline magnesium metal Mg
Garnierite (Ni,Mg)3Si2O5(OH)4
Now for the cache!
The cache is the usual camoed ammo can. Take the forest road until
you come to the red City of Bremerton Watershed sign. Everything
beyond this is city land. Don't go in there. The city takes
trespassing seriously. The cache is within 30 feet of the gate. The
hardest part of the cache is actually getting there. Expect a four
mile round trip, depending on your route. The flattest way in is to
park at the Gold Mountain Trailhead, but this adds about two miles
to the trek. Parking at the Quarry Road on Green Mountain Road is
most direct, but can be pretty steep.
An interesting aside, when I was placing this cache, I experienced
that rarest of occurrences: The sky was free of GPS satellites. I
had to sit around for over an hour just to get three of the buggers
to register. EPE was 45 feet.