Geol. 198B Homework #3: Physical Properties of Gems 20 pts. **

The answers to the following questions will be found in the text reading assignments, and the assigned web essays for Lesson 3.

Required Format: A 2 point penalty will be deducted for not following the format described (even if all the answers are correct)!

Send the answers to me, as an email through WebCT. Use "Homework #3" as the subject line.

As the body of the email, the answers should be arranged vertically, single file, like so:

1. b

2. quartz

3. False

4. etc....

All required answers for Homework #3 are: a multiple choice letter, True/False, or a single word.

When the time period for homework submission has passed, grades will be posted which you may then view using the "My Grades" function of WebCT through the course home page.


1. Lines of cleavage in a gemstone are usually parallel, perpendicular or ______________ to the crystal faces.


2. The chromophore responsible for Moldavite's green color is:

a. chromium

b. iron

c. copper

d. nickel

3. True or False. A bright green quartz drusy has probably been dyed.


4. Both black nephrite with magnetite inclusions and __________________ come from California.

a. Vonsen Blue nephrite

b. greenstone

c. pounamu

d. Polar jade

e. white nephrite

5. What is the indicator mineral used in calibrating the 2.71 heavy liquid used in specific gravity testing?

a. copper

b. quartz

c. calcite

d. diamond

e. Clerici's solution

6. The iridescence of fire agate is caused by thin layers of the mineral:


7. Nephrite and jadeite are both:

a. amphiboles

b. pyroxenes

c. aggregates

d. fibrous

e. granular

8. The cleavage of fire agate is:

a. perfect in four directions

b. easy in two directions

c. indistinct in one direction

d. conchoidal

e. there is no cleavage

9 Moldavite is named for:

a. the location where it is found

b. the fact that as a glass it can be molded into any shape

c. the geologist who first described it.

d. none of the above

10. True or False: Most of the nephrite in today's market comes from China.


** "A Word to the Wise": In order to get the full 20 points on this, and every other homework, you must have all the correct answers, they must be in proper format as described above AND your email to me must be received and logged in by WebCT before the closing time for the assignment. As there are inevitable computer downtimes, disconnects and other such issues, I suggest that you do not wait until the very last moment to attempt to submit the work.