TRADING IN GEMS
The Cleveland Museum of Natural History
1 Wade Oval Drive, University Circle
Cleveland, OH 44106
Level: Grades 4 - 8
Estimated Time Required: 45 minutes
Anticipated Learning Outcomes
- Students will become aware that most gemstones are minerals.
- Students will understand how quality affects gemstone
- Students will discover how desirability is a personal
- Students will see how marketing and name recognition
The purpose of this activity is to demonstrate
how individual subjective taste is a factor in value (in terms of cost)
in gemstones, which have their origin in the natural realm of minerals.
Gems are also an exciting and intriguing aspect to the study of minerals
which can help to spur flagging interest and lead to deeper understanding
of mineral and crystal formation.
- Small plastic zipper bags or paper envelopes, one for
each student in the class.
- A variety of tumble-polished stones of as many different
types as possible, to make it interesting, at least 6 - 8 types. Sources:
Ward's Scientific Inc.; the numerous ads for tumbled material in each issue
of the Lapidary Journal; or contact local lapidary club for possible donations
or low cost sources.
- Fill bags ahead of time with 3 or 4 samples for each
student. Bags cannot be filled with the identical mix of stones. Variety
is important for activity.
- Discuss minerals in general. (This may be done in previous
- Discuss gems - i.e. natural minerals that have been cut,
shaped and polished for human adornment or use. To qualify as a gem, a
mineral must possess beauty (of some kind), durability, and rarity.
- Show bags to the students. Tell them that the stones
are all genuine gemstones. Give them the conditions of the trading activity.
They should look at their own stones and decide which, if any, they like.
They will then have an opportunity to trade with others. They will have
10 - 15 minutes to move around the room and see what they might like better.
Any trade of stones that both parties agree to is OK. One-for-one, two
for one, etc. is fine as long as both parties agree. Salesmanship may be
an important part of getting others to agree to a trade. Don't talk down
your own stones and then expect someone else to want them. No other commodities
other than the stones may change hands; trading involves only the stones.
At the end of the time, they may choose and keep one, and only one, of
the stones that they have in their possession.
- After these instructions, pass out the bags and allow
the students time to move around and trade stones. Be prepared to have
students ask what each stone is. I do not give out that information at
this point. Many students will have at least heard the names before. What
they hear will color their reaction and their judgement. For this part,
it is better if they simply go by what they like.
- When the trading activity seems to be slowing down, give
them verbal warning that time is running out and then call for a return
to their seats. Ask students about their trading activity. You might want
to see how many have only one stone left and how many have parleyed their
number up to six or more.
- Have students choose the stone in their possession that
they want to keep. That sounds easy; it is not! Be prepared for agonizing
over the decision. They should put the one they want back in the bag. You
may then go around and collect the rest.
Results and Discussion
- Take some time for discussion of their choices: what
they chose and why.
- At long last, name the various types of stones that were
present in the samples. Groans and moans! All will want to know what the
stones are worth as they hear names like amethyst, tigereye, garnet, agate,
etc. As you will know, having purchased the material, almost all can be
had for 10 - 25 cents apiece or less. This will also be a shock.
- Discuss why these chips and pieces are not as expensive
as they expected:
- Beauty: What are the quality of these stones? Is the
color intense and true, clean, uniform, or are there spots and bands of
color and shadows of milky appearance? If they are supposed to be banded,
as in some of the agates, maybe the bands are too wide and not sharply
divided. Are there cracks and other kinds of flaws in the stones?
- Style of stone: Irregular shape indicates tumble-polished
stone - the quickest and easiest way of getting a polish on a stone. It
doesn't take a lot of human work and time to get a whole batch of stones
polished in this fashion, as opposed to the cuts we see more often in expensive
jewelry. Cabachons - dome-shaped stones, are a cut used most often for
translucent or opaque stones to show off colors and patterns in the stone.
Faceted stones - the "sparklers", have flat surfaces cut at precise
angles to reflect the light and produce sparkle. This is the most labor
intensive cut to produce and is used for transparent stones.
- Setting: When buying finished jewelry, the setting of
gold or other precious metals adds to the price, sometimes costing more
than the stone itself.
- You may be able to arrange for someone from a local lapidary
club to come in and provide demonstrations of tumbling and polishing stones
or to talk about mineral collecting.
- Collect jewelry ads from magazines and newspapers. Discuss
marketing methods, etc.
- Have students do reports on various gemstone types and
their origins, or on the role of gemstones in history.
With careful observation of their students during the trading
period, teachers may gain some interesting insights!
Recommended Reading for Teachers
BRUTON, E., 1986, Legendary Gems or Gems That Made
History, Chilton Book Co.
DIETRICH, R.V., and SKINNER B.J., 1990, Gems, Granites and Gravels, Cambridge
University Press, p.. 27-29.
Planet Earth series, Time-Life Books, 1983, Gems.
SCHUMANN, W., 1977, Gemstones of the World, Sterling Publishing Co., Inc.,
Recommended Reading for Students
STANGLE, J., 1990, Crystals and Crystal Gardens
You Can Grow, Franklin Watts.
SYMES, R.F. and HARDING R.R., 1991, Crystal and Gem, Eyewitness Books.