Question 1

The most famous gem in the world is the Hope Diamond, currently on display in the Smithsonian Hall of Gems in Washington DC.  Why is it so famous?

Accepted Answer

It's cursed. - Okay, this is a bit misleading since most people don't believe in curses and the Hope Diamond is blue, but this is a case of legend creating a reputation that exceeds fact. The diamond is far from the largest (only 45 carats, less than 1/10 of the record of 545 carats), and the current record for the most expensive is held by a 59 carat diamond called the Pink Star which sold for over $71 million.  If it were sold today, it's almost certain the Hope would break that record, but we will never know.

Question 2

The word "diamond" is from the Greek "adamas".  What does it mean?

Accepted Answer

Unbreakable - It's ironic that "unbreakable" is one thing diamonds are NOT.  While they are the hardest natural substance, they can be broken from impact... as many diamond wearers have discovered to their dismay.

Question 3

What is popularly considered the most valuable type of gem?

Accepted Answer

Ruby - While diamond has the best marketing due to DeBeers, rubies over 1 carat are far more in demand. The larger they get, the greater the price difference grows.  A 3-carat diamond usually runs just a bit over 3 times what a 1-carat of the same quality costs.  Rubies gain value much faster with size due to their rarity in larger sizes.

Question 4

Many gemstones, like diamonds, are actually colorless when they are in their "pure" state.  What gives many gemstones their color?

Accepted Answer

Impurities - While other factors can make a difference in how gems appear, color most often is the result of small quantities of impurities from another element such as metals like iron, chromium, or titanium.

Question 5

Some gems are a unique species unto themselves.  Others are different color varieties of the same mineral.  Aquamarine is a variety of beryl.  Which is another member of the same family?

Accepted Answer

Emerald - Emerald is a variety of beryl that gets its color from trace amounts of chromium.  Curiously enough, the same chromium gives ruby its red hue.

Question 6

Garnets are another family of gemstones.  A new variety of garnet dubbed "tsavorite" was discovered in Tanzania in 1967.  What made it unusual?

Accepted Answer

Color - Tsavorite is a variety of grossular garnet which comes in a variety of colors, but none of them are the traditional red usually associated with garnet.

Question 7

Amethyst is a variety of purple quartz.  The ancient Greeks named it for a particular magical property they attributed to it.  What did they think it did?

Accepted Answer

It prevented drunkenness - Amethyst was highly valued in ancient Europe, especially after the laws of Rome made it illegal for anyone but the emperor to wear "Imperial purple".

Question 8

A lesser know gem that has been historically mistaken for many other gems because of its incredible variety of colors.  What is it?

Accepted Answer

Tourmaline - Tourmaline occurs in the widest variety of colors of any gemstone, partially due to differences in chemical composition.  Some have said tourmaline's chemical formula looks more like something a mad alchemist might create and not a legitimate gemstone.

Question 9

Padparadscha is a lotus-flower-colored (pink to orange) gem that is more sought by Asian buyers than in the west.  What type of gem is it?

Accepted Answer

Sapphire - Most gem padparadschas are found in Sri Lanka, southeast Asia, and east Africa.  They are as rare as top-color blue sapphires.

Question 10

Rubies and sapphires are the same gemstone, simply different colors.  What is their generic mineral name?

Accepted Answer

Corundum - Corundum has a good variety of colors, including the popular star ruby and star sapphire varieties.

Question 11

Alexandrite is a rare gemstone named for the Russian czar ruling when it was discovered in the Ural Mountains.  What makes it so unique?

Accepted Answer

It seems to change color - Alexandrite doesn't actually "change" color, but it appears green in daylight and fluorescent but red under incandescent light.  Since red and green were the colors of the Russian Imperial family, naming for Czar Alexander was a wise political choice.

Question 12

Opal is a popular gemstone and one of the birthstones for October.  What makes it different from most other gemstones?

Accepted Answer

It contains water in its structure - There are other gems that are iridescent, but due to precious opal's unique, permeable structure, it's not even a true mineral.  It's considered an "amorphous mineraloid silica".  The water in its structure makes opal one of the more unstable gems, subject to spontaneous cracking even when stored and not worn.  This characteristic partially led to opal developing a reputation for bad luck.

Question 13

Hardness in a important consideration in gemstones.  Which scale is used to measure a mineral's hardness?

Accepted Answer

Mohs - Invented in the early 1800s by German mineralogist Friedrich Mohs and is still used today, the Mohs scale is a scratch test that is so simple it's still popular today.

Question 14

While gems come in a wide range of hardness, jewelers prefer to use gems in rings to at least how hard?

Accepted Answer

7 - Since silica (hardness 7) is one of the most common constituents of the Earth's crust, most household dust has a high level of silica in its makeup and so will scratch gems that are softer.

Question 15

Another gem that was a more recent discovery was made in 1967 in East Africa.  This blue to violet crystalline gem was given its new name by a vice-president of Tiffany's.  What is it called?

Accepted Answer

Tanzanite - Tanzanite is technically "blue zoisite" but Tiffany's wisely decided a new name would be easier to market... hence "tanzanite".

Question 16

When diamond is a 10 in hardness, corundum (ruby & sapphire) is a 9 in hardness, what is used to represent 8 on the scale?

Accepted Answer

Topaz - The Mohs scale rates as follows: 10 (diamond), 9 (corundum), 8 (topaz), 7 (quartz), 6 (orthoclase), 5 (apatite), 4 (fluorite), 3 (calcite), 2 (gypsum), and 1 (talc).

Question 17

Most cut gems are either faceted with a number of flat faces or cut in a smooth dome similar to the one pictured.  What is this smooth dome shape called in reference to gems?

Accepted Answer

Cabochon - Cabochon (pronounced kab-uh-shahn) is from the French "caboche" meaning 'head'.

Question 18

In faceting, each shape has a specific descriptive name.  The gem below with its elongated elliptical shape and points at both ends is called what kind of cut?

Accepted Answer

Marquise - The marquise cut is often considered a particularly elegant shape, but the shape has the drawback of sacrificing some brilliance due to the shallow angles the pointed ends necessitate.

Question 19

Anyone who has seen Jurassic Park knows that amber is fossilized tree resin, but it has one characteristic that makes it unique among gems.  What is it?

Accepted Answer

It floats in salt water - While amber does indeed glow under ultraviolet, and while it is organic in origin, both of these are common to a number of other gems.  It's amber's low density that allows it to float in sea water that is unique among gems.

Question 20

The British Crown Jewels proudly display the Black Prince's Ruby in the Imperial State Crown.  But there's something different about this gem.  What is it?

Accepted Answer

It's not a ruby - Nope, it's not a ruby.  It's actually a red spinel which is chemically similar to a ruby but not as rare.  Mistakenly calling red spinels "rubies" isn't unique to this stone.  Before gemology became a science, many red spinels were misidentified this way.

Gems and Gemology Quiz: the Flowers of the Mineral World

2) The word "diamond" is from the Greek "adamas". What does it mean?

3) What is popularly considered the most valuable type of gem?

4) Many gemstones, like diamonds, are actually colorless when they are in their "pure" state. What gives many gemstones their color?

5) Some gems are a unique species unto themselves. Others are different color varieties of the same mineral. Aquamarine is a variety of beryl. Which is another member of the same family?

6) Garnets are another family of gemstones. A new variety of garnet dubbed "tsavorite" was discovered in Tanzania in 1967. What made it unusual?

7) Amethyst is a variety of purple quartz. The ancient Greeks named it for a particular magical property they attributed to it. What did they think it did?

8) A lesser know gem that has been historically mistaken for many other gems because of its incredible variety of colors. What is it?

9) Padparadscha is a lotus-flower-colored (pink to orange) gem that is more sought by Asian buyers than in the west. What type of gem is it?

10) Rubies and sapphires are the same gemstone, simply different colors. What is their generic mineral name?

11) Alexandrite is a rare gemstone named for the Russian czar ruling when it was discovered in the Ural Mountains. What makes it so unique?

12) Opal is a popular gemstone and one of the birthstones for October. What makes it different from most other gemstones?

13) Hardness in a important consideration in gemstones. Which scale is used to measure a mineral's hardness?

14) While gems come in a wide range of hardness, jewelers prefer to use gems in rings to at least how hard?

15) Another gem that was a more recent discovery was made in 1967 in East Africa. This blue to violet crystalline gem was given its new name by a vice-president of Tiffany's. What is it called?

16) When diamond is a 10 in hardness, corundum (ruby & sapphire) is a 9 in hardness, what is used to represent 8 on the scale?

17) Most cut gems are either faceted with a number of flat faces or cut in a smooth dome similar to the one pictured. What is this smooth dome shape called in reference to gems?

18) In faceting, each shape has a specific descriptive name. The gem below with its elongated elliptical shape and points at both ends is called what kind of cut?

19) Anyone who has seen Jurassic Park knows that amber is fossilized tree resin, but it has one characteristic that makes it unique among gems. What is it?

20) The British Crown Jewels proudly display the Black Prince's Ruby in the Imperial State Crown. But there's something different about this gem. What is it?