How Much Do You Know About These Precious Gems and Metals?

John Miller

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About This Quiz

There are roughly 4,000 distinct types of minerals on Earth. But just a few -- thanks to happenstance and human longing -- are considered precious. How much do you know about our planet's precious gems and metals?

What makes a metal "precious"?

Precious metals have a couple of things in common. One, they're rare. And two, they have economic value, either in jewelry or in some sort of industrial application.

With regard to gold, what does the term "karat" mean?

Karat is a term that refers to the gold's purity. Pure gold is very soft, so it's typically mixed with other metals to make jewelry.

Almost all natural rubies are treated for which purpose?

Most natural rubies undergo a process that improves their reddish color. This is a standard and approved practice in the gem industry.

Pure gold is how many karats?

It's the phrase jewelry marketers love to throw around -- 24-karat gold. That's the purest form of gold.

What is the only thing that can scratch a diamond?

Diamonds are the hardest natural substance around. The only thing that can scratch them? Another diamond.

Which of the following is NOT a precious metal?

Copper is very useful, but it's not a precious metal. The precious metals are gold, silver, platinum, palladium, ruthenium, rhodium, osmium, iridium, scandium, hafnium and beryllium.

The United States Bullion Depository is essentially a huge storehouse filled with which precious metal?

Opened in 1937, the United States Bullion Depository is brimming with much of the U.S. government's gold supply. There is approximately $180 billion worth of gold in the depository.

It takes at least ____ years to form a diamond.

It takes an incredible amount of time -- at least one billion years -- to form a diamond. Some diamonds are three billion years old.

True or false, is the term "karat" the same thing as "carat"?

False, karat denotes the purity of gold. Carat, on the other hand, is a measure of a gemstone's weight.

The diamond trade has two primary categories, the gem-grade category and the _____-grade category.

Diamond sellers break the diamond trade into two categories: gem-grade, for jewelry, and industrial-grade, those used for a vast array of industrial purposes. Most mined diamonds aren't appropriate quality for jewelry, so they wind up as industrial products.

Which of the following metals is the most precious?

Platinum is incredibly rare. So rare, that it's one of the most precious of the precious metals. It's strength and lack of reactivity make it useful, and it's beautiful in jewelry, too.

What's a major trait of silver?

Silver isn't just beautiful, it's useful, too. It's a very good conductor of electricity. It's also an excellent thermal conductor.

Pearls are the only gemstones produced by ______.

Pearls are the only gemstones in the world that are produced by a living organism. They are found in wild oysters ... but just 1 in 10,000 or so oysters produce a pearl.

Palladium is a precious metal that's important in which advanced product?

Palladium is used in car catalytic converters. The metal helps to break down the pollutants in car exhaust so that they aren't so damaging to the environment.

The biggest uncut, gem-quality in history is the Cullinan Diamond. How much did it weigh?

The Cullinan Diamond was mined in the area of South Africa in 1905. At about 1.3 pounds, it's still the biggest uncut gem-quality diamond ever found.

Where is the Cullinan Diamond, the biggest gem-quality diamond ever mined?

The diamond was given to King Edward VII of the United Kingdom in honor of his birthday. It was cut into smaller diamonds that have been passed down to Queen Elizabeth II. Oh, to be a queen.

Rhodium is a precious metal known for which characteristic?

Rhodium is cherished in part for its high strength, which makes it suitable for a huge range of industrial purposes, from glass fiber creation to airplane spark plugs.

Pyrite is a non-precious metal that's often confused with _____.

Pyrite is often called fool's gold. It looks a lot like gold, but if you tried to sell it on the market you'd look like, well, a fool.

Palladium has a fantastic ability to absorb what?

Palladium has an amazing trait, in that it can absorb huge amounts of hydrogen. It's like a metal sponge, and it makes palladium useful in a lot of different industrial and automotive products.

Where do diamonds form?

Diamonds are nearly 100 percent carbon, and they form due to high temperatures and incredible pressure -- about 100 miles below the Earth's surface. They're then pushed towards the surface by volcanic activity.

True or false, can humans actually farm pearls?

Humans expend a lot of energy farming pearls in carefully-controlled conditions. Most of them are made in a freshwater setting -- but wild, saltwater pearls are much more valuable.

Most of the world's gold supply is used for which of the following purposes?

Gold is incredibly popular for personal adornment. The vast majority of the gold that's mined every year is used in jewelry.

Silver is often used in which industry?

Thanks to its great ability to conduct electricity, silver is widely used in the electronics industry. But don't go raiding your old VCRs for silver, because the metal is only used in small amounts.

Platinum is a precious metal that has which trait?

Platinum is one of the least reactive metals known to humans. It almost never corrodes, one of the reasons it's so valuable for so many different purposes.

What color is an amethyst gemstone?

Amethyst is a type of quartz that's violet in color. It's popular in jewelry and it's also the birth stone for February.

What's one primary trait of gold?

Gold is very malleable and reflective. That reflectivity is great for jewelry, of course, but it also makes gold appropriate for windows and radiation shielding.

True or false, are sapphires only blue in color?

Sapphires are typically blue. But they also come in green, orange, purple or yellow, and they are sometimes even a blend of multiple colors.

Which precious metal is often collected through "panning"?

As lovers of Old West lore surely know, panning is a means of separating gold from other minerals. In the days of the Gold Rush, a few hardworking (and lucky) people panned for gold and created a fortune for themselves.

What color of diamond is the rarest (and most expensive) of all diamonds?

Red diamonds are the holy grail of all diamonds. And at a price of roughly $400,000 per carat, they are ridiculously expensive.

What causes the red color in a red diamond?

Gemologist debate the source of a red diamond's coloring. But researchers suspect that it has to do with the way atoms are arranged when the diamond forms.

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