24) Native Element Minerals Pt. 1

(Opening music) Welcome back mineralogy fans! It’s a big episode today as we come to
the last to the seven major mineral groups, the native element minerals which
have an orderly arrangement of atoms of one element. As a quick rundown of the
elements on the periodic table that can form crystallized minerals, we have:
aluminum, antimony, arsenic, bismuth, carbon, cadmium,
chromium, copper, gold, indium, iron, iridium, lead, mercury (if you get it down below -38 C), nickel, osmium, palladium,
platinum, rhenium, rhodium, selenium, silver, silicon,
sulfur, tantalum, tellurium, tin, titanium,
vanadium, and zinc. We won’t cover all these in
detail, but it would be remiss of me to be at
the Colorado School of Mines and not mention copper, silver, gold, palladium, and
platinum, all of which display metallic luster, and
form with the sulphides in hydrothermal deposits, or in some igneous rocks. Copper is at a hardness 2.5 to 3, and is
usually copper colored, though browns to red are possible. It has a
rose-colored streak, and oxidizes to the familiar green patina. The specific gravity is 8.94, which is
the highest density mineral we’ve seen so far, so it’s mass gives clue to
copper’s identity The name comes from Cyprus, Cupres, which was the principal source of copper
in ancient Greece. It can be used for decorative purposes, and loves to grow in
dendritic crystal form, meaning branching like a tree.
Industrially, copper is used in the electronics world
due to copper’s ability to conduct heat and electricity well. Because copper is
ductile, that is it can be drawn out into wires,
so copper is a common metal of electrical wiring Alloyed with tin, it becomes bronze,
and thus took humans out of the Stone Age. From
ancient to modern times, copper has been used for coinage as well. Malleable, you can pound it into thin
sheets, sectile, you can cut it with a knife, and
ductile, you can draw into wires; resistance to corrosion and ease of being alloyed with other
minerals, are valued properties for copper and all of our following metallic
native element minerals. And as we go, we’ll have even greater resistance to
corrosion. Silver has one more property copper doesn’t,
which puts it into a whole new category known as the precious metals. That extra
property is rarity. Silver and the other precious metals are
much rarer than copper, so you are not likely to encounter the
native precious metals in nature unless you’re trained to know where to look, but if you do happen to see them, maybe
at an estate sale or something, your should be prepared to identify them.
The precious metals include silver, gold, platinum, and palladium. Silver is a
mineral name that has more clouded origins, and in many of its past uses
has been synonymous with money. The earliest possible origin is from Akkadian “sarpu”, which came from “surapu”, meaning “to
smelt and refine”. With a characteristic grey, to grey-white, to silver color, about the only other test needed is
picking it up as we have a new specific gravity record holder at 10 to 11
times the density of water, though we’ll find later we still need to
distinguish from palladium by its hardness. Like copper, it has a hardness of 2.5 to
3, so it leaves a streak, which is silver-white in color, and you’re just
going to have to trust me on that because I don’t want to waste my silver. Besides silverware and jewelry, silver has a
few other uses. Silver paints are used for printed
circuits, and silver leaf is used in mirrors due to
its high reflectivity, though as any of us know with real silverware, it does tarnish due to oxidation over time. Silver is used for electrical contacts and solder, in batteries, and as a brazing alloy.
Mineral silver crystals can grow in massive, dendritic, or wiry crystal habit. This wire silver is associated
with calcite crystals which happened to be fluorescent under UV
light. Neither silver, nor any of the other
precious metals, fluoresce under UV light. But the next precious metal will
fluoresce under x-ray light. Gold is the most famous of the precious
metals and can be identified, and its purity determined by x-ray fluorescence. The name gold has
been variously associated with root words meaning “to shine” or “yellow” due to its
characteristic golden yellow color and highly reflective metallic luster. Coming in at 19.3 times
more dense than water, we have our new heavyweight champion in
gold. So the color and mass pretty much give
this mineral away. Anyone who has watched a show about gold
mining in sedimentary deposits know that shakers and pans are used to eject the
less dense minerals, while the dense gold stays behind. Gold, as with copper and silver, has a
hardness of 2.5 to 3, and can leave a streak showing
the gold color. Nope, not gonna demonstrate that either. We
discussed in the sulfide minerals how to tell pyrite, or fool’s gold, from real gold and you can
refer back to that for differences. Gold can take on a range of crystal forms
when it grows large enough to see, but most gold is scattered through their ore rocks, and the decision to mine such ore is
dependent on the concentration of gold in the ore, ease of mining the ore, ease of extracting
the gold or other precious metals from the ore, without significant pollutants, and the current price. Gold has been used
for jewelry and coinage for a long time, both in
relatively pure and alloyed states, and obviously
continues to be so. Malleable, ductile, sectile,
conductive of electricity, easily alloyed with the other metals, and
much more resistant to corrosion explains its wide array of uses
including in electronics as wires, relay contacts, switches, connectors, CPU’s, and computer chips; so whether
you are watching this on a computer or a mobile device, the information is being passed along by
gold components in your device. There’s a treatment for arthritis
involving the injection of dissolved gold salts, a cure for a rare condition where
people are unable to close their eyes completely in which gold compounds are
placed in the eyelids to weigh them down, and gold can protect us from harmful
radiation, even in very thin sheets. Gold polyesters
on the exterior of some space craft help regulate surface
temperatures by rejecting radiation. The malleability means you can take a
small amount and spread it over a large area, and many objects and structures use gold
leafing. And no winner is, the Gold Palace in
India. Union Station in Washington DC only gets
a grammy. Oh! It’s also used in dentistry. I’ve gots to have my grill on while I’m
cold lamping about my Mother Earth in full effect. But how much more dope to be kickin a
platinum grill. Heavy! In fact, this silvery metallic
precious metal is almost twice the density of silver coming in at the
calculated specific gravity 21.47, but most samples of platinum come
in closer to gold’s 19 times the weight of water. All the
other precious metals are about the hardness of calcite at 2.5 to 3, but
platinum is closer to fluorite at 4 to 4.5. It will leave a silvery
streak, which is a waste of platinum when the density would give it away if
you had a piece big enough to do a streak test with. As with gold, this density is used to
sort it from stream sediments, and the name “platnum” comes from the Spanish “Plata”, for a
river in which it was found. this metal too has been used as coinage and jewelry for millennia, and you might think that having all the
great properties of gold, it would have about the same uses. Platinum, however, is mostly used in catalytic
converters of our cars and trucks. So if you’re watching this while driving,
don’t. But besides your using it to regulate
the pollution from your favorite form of transportation, platinum is also used as a catalyst to
make benzene, nitric acid, and silicone. We use platinum
as part of chemotherapy drugs to fight cancers, and it is involved in the manufacture of
wind turbine engines, LCD screens, and computer hard disks, oxygen sensors, thermocouples, spark plugs, and, yes, platinum is used in dentistry so
I can get my dope grill G! Yeah boy. And you can measure how
dope that is because the original standard for a meter was defined by a
platinum rod, and the standard for a kilogram is still
defined by a platinum mass, and platinum is used as a standard
hydrogen electrode to measure relative reduction-oxidation potential of other
materials. Or you can measure time, in some of the most sophisticated watches
whose components include platinum parts, which neither corrode nor wear down as
easily as gold. And that second quality is another big
leg up on those other precious metals, which will wear down rather easily if used as mechanical parts.
According to the Advanced D&D Players Handbook, 1st ed. 1978, the relative value of copper to gold is 200
copper pieces equal one gold piece. Silver only takes a 10th of that; 20 silver
pieces to equal one gold piece. There’s some
electrum in there, which is an alloy of gold, silver, and copper. So we’ll pass
by that, and see that it takes 5 gold pieces
to equal 1 platinum piece. Many role-playing fans are quite certain
platinum is more valuable than gold, but as of 2015
when I’m making this, copper is about 17 cents per ounce, silver is
at $16 per ounce, gold is $1180 per ounce, and platinum is $1,125 per ounce. So I guess since the time I was
fighting and training dragons, and laying siege to my friends’ castles, the relative values of these native
element minerals has changed. Or not. And the Players Handbook doesn’t
even have our last precious metal mineral palladium, which is presently valued at $775 per ounce. This one is a bit harder to tell from silver,
as it too has a silver metallic luster and a
specific gravity around 11. But we can differentiate by its hardness,
which is well above the 2.5 to 3 of silver, with palladium coming in at a hardness
of 4.5 to 5, closer to apatite. Palladium is more elastic than ductile
too, but still ends up in many of the same uses as silver and gold. And that covers the precious metals, but
we are not done with the native elements yet. When we come back next time, we finish off
the native elements and end our tour of the major mineral groups,
when we find out what nature can order up from sulfur and carbon on our menu.

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