SPRING 1 9 9 6 CORNERSTONE Journal of the Accredited Gemologists Association TUCSON REPORT by David Harris This year the Tucson conference with physical properties of miner- David Johnson was our instructor was presented by the University of als as a function of structure and the remainder of the second day Arizona Geoscience Department chemistry and lab exercises to which we spent in the Santa Rita and included lectures on the funda- determine the physical properties Mountains panning for minerals. mentals of crystallography and of crystals. The final lecture of the Minerals such as pyrite, garnet, mineralogy and a fortune hunting day was presented by noted dia- and gold were found during this field trip in the mountains. mond geologist, Dr. Tom McCand- exercise, however none of the finds less, on the location of gem was large enough to prevent the DAY ONE deposits worldwide from the view- return to regular employment. Conducted by Frank Mazdab, the point of a geologist. The day ended Special thanks to all the partic- first lectures on Day One reminded at 6:30 PM with everyone going to ipants and instructors who made us how long it had been since we their rooms to digest this enor- used the periodic table and dis- mous amount of information and this a learning experience so enjoy- cussed atomic structure. Frank prepare for a day in the mountains. able. Next year we are planning started the day by passing out a another "Learning Experience in 100 page workbook filled with won- DAY TWO Tucson" in conjunction with the drous charts and tables. As he On Day Two Dr. Peter Kresan lec- University of Arizona. started his lecture, we knew we tured on the movement of tecton- After the conference, Past Presi- would receive far more than our ics forming the mountains sur- dent Joe Tenhagen presented me "moneys worth". The first day rounding the Tucson basin and how with an article that better explains included lectures on basic crystal- the various mineral deposits the type of information we dis- lography and basic crystal struc- occurred in the area in a presenta- cussed during the conference. ture followed by a hands-on labora- tion entitled, "Geology of Arizona (See page 3.) Thank you Joe, for tory. After lunch we continued and the American Cordillera". sharing this information. TOWARD A issues about gem treatments, the officers and membership "in grading standards, appraising, step" working toward a common SHARED VISION new technology, and many, many goal and objective for any signifi- By Craig Lynch more. Our industry has resolved cant length of time. I tend to some of these issues, others believe that nobody is at fault for During the 10 years I've spent as still stand without agreement this short term success that is fol- a member of the Accredited or resolution. Even in these lowed with disorganization. I Gemologists Association I've seen unresolved issues, I've found that believe that this happens primarily great benefits from belonging to the open forum provided by AGA because of slightly differing the organization. I've made many has been of significant benefit. visions of our organization. This friends and benefited from the net- However, I have noticed an on is complicated by the fact that work of good gemologists. This going problem in AGA. For some in our small organization time, organization has successfully reason, it seems that it has been money, distances between addressed many controversial almost impossible to keep all of members and physical resources (continued on page 2) AGA • CORNERSTONE • 1 SPRING 1 9 9 6 IN MEMORIUM Antonio Bonanno, founder of the Accredited Gemologists Association, AGA is a nonprofit research, education and ethics died recently after a long illness. organization, benefiting professional and avocation- In addition to the AGA, Mr. Bonanno founded the Columbia School of al gemologists as well as the consumer interest. Gemology in Washington, DC., and the National Gem Appraising Membership programs include advanced gemo- logical education seminars, professional computer Laboratory. He was a Distinguished Fellow of the Gemological software reviews and workshops, and the AGA- Association of Great Britain and Master Gemologist Appraiser of the Certified Gemological laboratory Program. American Society of Appraisers. We are grateful for his mind, his talent and the creativity he brought to his life. Think About It "Never doubt that a small group of commit- ted people can change the world. Indeed, it is CORNERSTONE very often the only thing that does. is a quarterly publication of the Accredited Gemologists Association. Paid for through Margaret Mead membership dues, this publication may not be purchased commercially. The opinions expressed within are those of the individual authors. AGA can assume no liability for (continued from page 1) these statements, which are offered entirely are in very limited supply. These "The mission statement is intend- for the purposes of informed professional limited resources seem to magnify ed to serve leaders of organiza- discourse and education. the differences in shared vision. tions as an expression of their vision and sense of stewardship. Copyright 1996, Accredited Gemologists Associa- Just how important is it to have a , tion common shared vision in an orga- It attempts to encompass in one All Rights Reserved nization? brief paragraph, the core values of Let me paraphrase Dr. Stephen the organization; it creates context For information regarding Cornerstone, that gives meaning, direction, and contact Lorraine Lopezzo at: Covey from his book Principled coherence to everything else." 41 East Mill Road, Suite 2, Centered Leadership. Long Valley, NJ 07853 "Vision is the best manifestation of Development of mission state- creative imagination and the prima- ments in the largest corporations Board of Directors ry motivation of human action. It's during the past 20 years has been President: the ability to see beyond our pre- at the core of the revolution in cor- Leo J. Schmied sent reality, to create, to invent porate culture, management style 1st Vice-President: what does not exist, to become and increased productivity as well Thom Underwood what we are not. It gives us capac- as efficiency. 2nd Vice-President: It is my belief that a well thought Joseph Du Mouchelle ity to live our imagination instead Secretary: of our memory. More than any out mission statement would be of Melinda H. Adducci other factor, vision affects the great benefit for AGA and have the Treasurer: choices we make and the way we following results: David L Harris spend our time." A mission statement will set the I would like to suggest the at the standard for short term planning Board of Governors AGA create a Mission Statement. and development and provide a Stanley P. Cohen No, not some pleasant, "feel good" consistent long range framework Therese S. Kienstra phrase to hang on the wall or put for all decisions made by the B. Young McQueen into a pamphlet. I mean a real executive board and the board of Anna M. Miller thoughtful approach to what we directors. This mission state- Larry Phillips want AGA to be, say 10 to 20 years ment also will guide and lift the Sharon Wakefield down the road. goals and objectives above and Just what is a good mission state- beyond any one administration for ment: Again, Dr. Stephen Covey... decades to me. (continued on page 8) AGA • CORNERSTONE • 2 SPRING 1 9 9 6 THE HEXAGONAL CRYSTAL SYSTEM By Joseph W. Tenhagen F.G.A., G.G., N.G.J.A. Most of you have had sufficient gemological training either from the GIA or GAGB to know that the hexagonal crystal system produces seven of the twelve principal birth stones. Whether there are six or seven crystal sys- tems is not the issue in this article; the intent is to broaden the readers depth of knowledge concerning the hexagonal crystal system. A. All crystals have a definite symmetry shown by the arrangement of their crystal faces which enables tielve,;//3 one to group them into different classes. The exter- nal crystal faces are the result of the three dimension- A/dtAtew al internal order of atoms in the crystal structure. The different types of symmetry elements in the Figure 4. hexagonal crystal system are: B. It is common to use a symmetry notation in any 1. Symmetry plane: A symmetry discussions relating to the crystal systems. In plane is an imaginary plane that Figure 1 . describing the symmetry of a crystal, it is convenient divides a crystal in half with each to use a shorthand notation for symmetry elements. half being a mirror image of the other. See Figure 1. A rotation axis is indicated by A n where n is 1-fold, 2-fold, 3-fold, or 6-fold. 2. Symmetry axis of rotation: A symme- try axis is an imagi- An axis of rotoinversion is indicated by CAR, nary line through a // where n is 1-fold, 2-fold, 3-fold, or 6-fold. crystal about which ; CD A plane of symmetry is indicated by P the crystal may be \\ A center of symmetry is indicated by C. rotated to repeat With this notation the symmetry of a crystal with itself in appearance a center of symmetry; one axis of 6-fold rotation one, two, three, or ------', symmetry; three axes of 2-fold rotation six times in a com- symmetry; and six planes of symmetry would be plete 360° rotation. 4, (;) written as: C, 1A6, 3A2, 6P. The symmetry rota- \ --- Lion axes in hexago- ‘, ,, Several of the more important gemstones crystallize lalnan nal crystals may be 3 in the hexagonal crystal system including seven of 1-fold (360°), 2-fold (180°), Fi 9 the birth stones.