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Home , Thulite, Zoisite

DELVINGS

The Newsletter of the Delvers Gem & Society

Volume 72 Number 9 September 2019

Ruby in (“Anyolite”) Arusha region of Tanzania Popular for cabochons and spheres Photo: Wikimedia, courtesy Hannes Grobbe

The mineral zoisite is a silicate of

calcium and aluminum. It is the orthorhombic polymorph of the monoclinic -group mineral ZOISITE as a and Lapidary Material (but zoisite is excluded from the epidote group, which currently is defined as monoclinic).

Like the epidote-group , zoisite generally occurs in metamorphic rocks.

To learn more, see article on page 5…

Zoisite, Variety This is the same double seen from two different positions: note the color change as the crystal is rotated 90° Photo: Wikimedia, courtesy Rob Lavinsky/iRocks

Delvers Gem & Mineral Society, Inc. - mailing address: P.O. BOX 112, Wilmington, CA. 90748 Please bring DONATIONS for GRAB BAGS to the NEXT (SEPT. 13th) MEETING Our club President, Peter German, has reserved a table for the Delvers at the September show of the Long Beach Mineral and Gem Society. His plan is to publicize our club, and perhaps make a few dollars by selling grab bags. Dianna and Emmalee Fowler have made fabric bags for the club’s use. We need donations of suitable small specimens (rocks, slabs, minerals, or fossils) to fill the bags.

We are now looking for volunteers to form a Nominating Commitee

Minutes of the July 31st & August 9th Board Meetings– Teresa Taylor & Andrew Hoekstra

A special board meeting held on July 31st was attended by several interested club members and the club’s vacant chair positions and the board’s management procedures were discussed. At the board meeting prior to the general meeting on August 9th, the proposal for a member sale/parking lot sale was discussed and the suggestion made that this could be held on a Saturday in October, if sufficient members are interested and permission is obtained from the church (it is unlikely to rain in October, and there are few local rock shows during that month). All documents associated with the treasurer position were handed over to Emmalee; if you are unsure whether you have paid your 2019 dues, please inquire of her (several members have not yet paid). Andrew scanned club documents, and “burned” them to a CD: one copy for the treasurer, and another to be kept by the club president.

Minutes for the August 9th General Meeting– Teresa Taylor & Andrew Hoekstra We had surprise visit by long-time members Jon and Lois Jean Fults, our dear friends. Esteemed guests included Pete Goetz and Russ Madsen from the American opal 2019 Board society, Mr. and Mrs. Wendell Oien, of the Holy Redeemer Lutheran President – Peter German Church, and our speaker. [email protected] Our August speaker was Walt Lombardo, of the Nevada Mineral and VP – Marvin Belcher Book Company, with a program on the gem minerals and history of [email protected] mining in San Diego County. Treasurer – Emmalee Fowler [email protected] Chuck Pierce displayed turquoise cabochons he has crafted, and he Secretary – Teresa Taylor gave a review of the club’s new library book on turquoise. Jon Fults [email protected] showed a piece of howlite drilled for a clock, which he donated; Jon Editor – Andrew Hoekstra also donated several other items for use as door prizes. Dale Harwood [email protected] displayed recently acquired mineral specimens: fluorescent Director – Guynell Miller hydrozincite from the Yellow Pine Mine in Good Springs, Nevada; the [email protected] uncommon mineral mottramite (lead copper vanadium hydroxide), Director – Dale Harwood 310-217-0551 from the Ojuela Mine in Mexico; Spanish cinnabar (mercury ore); and purpurite (manganese phosphate) from the Bull Moose (pegmatite) Mine in Custer, South Dakota. Sixteen members and six guests attended the meeting; many of those who stayed to the very end went home with a door prize.

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From the CFMS Newsletter, July 2019 equipment for the use of the members. Other clubs By Pat LaRue, CFMS Past President, 1996, 2000 have a “workshop” get together at a member’s home. A few clubs have claims or lease property on which While browsing through a largely ignored file of their members can prospect and/or collect material. articles gleaned from club publications during the time I was editing two or more club bulletins, I came • They publish a newsletter on a regular basis. across an article I wrote for the AFMS newsletter in • They recognize that whereas people might join a 1994. At the time I was serving as 2 VP for CFMS. club to learn more about the hobby, more will The observations made at that time are just as true continue their membership if they develop a sense of today as they were then–the only major thing that has belonging to the group. Perhaps the most important changed is the influence of technology in getting out committee in the club might be the one in charge of our message. hospitality. Clubs must make these newcomers feel welcome. CLUB SURVIVAL GUIDE FOR THE 90s • They make every attempt to minimize conflict The 1994 membership renewal numbers are nearly in within the group. Those in leadership positions must for the seven federations and their member societies. make every effort to keep their personal differences Unfortunately one of the things all of us may have in private. A club can only prosper and grow when the common is that those numbers may be lower than they energy flowing from its leadership is positive and were during the previous years. If this dangerous trend nurturing. Negative energy may not only drive away should continue over the next few years, one may not existing members, but may not only drive away have to worry about the future of the hobby existing members, but may actually discourage others organizations...there might not be any organized from joining the group. We must remember at all hobby to worry about! times that we are “hobby” organizations with which Can we do something about this downward trend? we associate to have fun and learn new skills. When Can we do something to hold our present numbers and you take away the fun and the sense of camaraderie, hopefully add a few? Perhaps if one looks at what the membership will suffer. some of the larger or more active clubs are doing, we • They focus the membership recruitment effort on all can find some suggestions. groups. We hear much about the importance of getting The more actively growing clubs all have one thing in “young people” involved. That’s great, but don’t common. The membership rosters are not only overlook the huge segment of the population that is expanding, but they continue to renew a larger either planning retirement in the next few years or percentage of the existing membership. Let’s examine have recently retired and want to try something new. some of the thing these clubs do to attract and retain In many parts of the nation, the population is as members. diverse as the aspects of our hobby. Why not involve more persons from other cultures in our hobby. • They promote the hobby in general and their club in particular. At least one club prints information flyers These are just a few thoughts that might help stem the which promote its activities and member benefits. downward spiral in which our numbers seem to be This same group sets up a gold panning booth and caught up. All of our creative energy needs to become equipment display at local schools and club shows and focused on increasing our membership and keeping lets the public experience the thrill of panning for real the majority of members we already have. Let’s talk gold. Despite the growing challenges to do so, most about our hobby in general and our club in particular. actively growing clubs continue to sponsor a show. Invite every acquaintance who shows an interest to a • They provide ongoing services to their members. A meeting...better yet, take them to the meeting, variety of activities which appeal to the majority such introduce them to the club members and get them as quality programs are a must. Some of the lapidary involved. If everyone invited just one interested friend groups have a workshop building and provide to join a club, our numbers would grow through the roof!

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SHOWS Sept 21, Long Beach: Long Beach Mineral & Gem Society, Expo Arts Center, 4321 Atlantic Ave. Hours: 10-5 Contact: Carol Kron & Karin Alvarez, 562-577-9044 [email protected], http://www.facebook.com/LBMGS/

September 7-8, Arroyo Grande Oct 13, Fallbrook San Luis Obispo Gem & Mineral Club Fallbrook Gem & Mineral Society South County Regional Center 800 West Branch Street 123 W. Alvarado St. Hours: 10-5 Daily 9 AM – 4 PM. [email protected]; http://www.slogem.org/show.html https://fallbrookgemandmineralsociety.wildapricot.org/ event-3512507 Oct 4-6, Vista Vista Gem & Mineral Society Oct 19, West Hills Antique Gas & Steam Engine Museum Woodland Hills Rock Chippers 2040 North Santa Fe Avenue First United Methodist Church, 22700 Sherman Way Hours: 10 - 4 daily. http://vistarocks.org Hours: 10 – 5. http://rockchippers.org/shows.html

FIELD TRIPS Oct 19-20, Yermo area (club claim), with the Whittier G&MS. Details to be announced…

PROGRAMS Sept 9 – Lake Superior Copper Agates, by Jack Hobart, at the Culver City Rock and Mineral Club 7:30 PM, 4117 Overland Ave. (Multi-Purpose Room at SW corner of the bldg)

The American Agate-Jasper Index: If you don’t have these yet, you will want to download them Created from photo submissions by rock hounds, with the goal to aid people with the identification of specimens UPDATED LINKS! www.dropbox.com/s/kzkfbqsgobmu1r6/2012%20Agate%20Index%20Vol%201%20Southwest.pdf?dl=0 www.dropbox.com/s/245z1myhotaanfw/2012%20Agate%20Index%20Vol%202%20Northwest.pdf?dl=0 www.dropbox.com/s/jicem1itdwljb81/2012%20Agate%20Index%20Vol%203%20California%20%5B1%5D.pdf?dl=0 www.dropbox.com/s/3gnozrpkwhjzu94/agate%20index%20vol%2010a%20California.pdf?dl=0 www.dropbox.com/s/l7263qgonw8weh8/agate%20index%20vol%2010b%20california%5B.pdf?dl=0 www.dropbox.com/s/2h92xwpikd1p7kd/Agate%20Index%20Vol%201.pdf?dl=0 www.dropbox.com/s/cs4fada74zpqsgf/Agate%20Index%20Vol%202.pdf?dl=0 www.dropbox.com/s/brleobs7d9l3gou/Agate%20Index%20Vol%203.pdf?dl=0 www.dropbox.com/s/drq3h5pnwoytwte/Agate%20Index%20Vol%204.pdf?dl=0 www.dropbox.com/s/5bph4o9218cifbs/Agate%20Index%20Vol%205.pdf?dl=0 www.dropbox.com/s/ge4yixnx1w4t9ak/Agate%20Index%20Vol%206.pdf?dl=0 www.dropbox.com/s/r649ybrjyqzme1m/Agate%20Index%20Vol%207.pdf?dl=0 www.dropbox.com/s/e067tsdz0o0b64s/agate%20index%20vol%208.pdf?dl=0 www.dropbox.com/s/ugt65x1s6ur4mzp/Agate%20Index%20Vol%209.pdf?dl=0 www.dropbox.com/s/z04uerbbzgtgl1y/2011%20Portfolio%20-%20Bob%20Rush%20Brazilians%5B1%5D.pdf?dl=0 www.dropbox.com/s/8nhm8qfby6xfwp6/2011%20Portfolio%20-%20Dan%20Heuer%20Lapidary%20Alphabet%5B1%5D.pdf?dl=0 www.dropbox.com/s/afvaxrk6rrk6cdj/2011%20Portfolio%20-%20Dan%20Heuer%20Rare%20Earths%5B1%5D.pdf?dl=0 www.dropbox.com/s/445fbbw5zj4mv49/2011%20Portfolio%20-%20Steve%20Haynes%20Lakers%5B1%5D.pdf?dl=0

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The Mineral Zoisite as a Gemstone and Lapidary Material – Andrew Hoekstra

Tanzanite is the sapphire-blue to violet gem form of zoisite. The are actually brownish when mined and turn blue by heat-treatment. Tanzanite is found in the Merelani area of Tanzania, associated with gneiss. Yellow, pink and greenish zoisite crystals also occur in this area of Tanzania. Crystals are elongate and prismatic, finely striated on their faces, and desirable for faceting as a gemstone. Large (to >3 cm) green crystals of zoisite are found in Switzerland (Gandegg), and large (to >8 cm) green or colorless crystals at several localities in Pakistan.

Tanzanite and other zoisite crystals exhibit - they change color when rotated in respect to the light source - and are trichroic, exhibiting three different hues when viewed along each of the three crystal axis. This occurs because each axis of an orthorhombic crystal is of a different relative length.

Massive green chromium zoisite (trade name anyolite) from Longido, Tanzania, is found with bright red ruby crystals and Wikimedia, courtesy Rob Lavinsky/iRocks black amphibole and, as ruby in zoisite, is popular for cabochons and spheres. Sometimes called anyolite, it is a metamorphic rock composed of green zoisite, red ruby (corundum), and blackish pargasite (amphibole). Many tons have been mined. When cutting and polishing, care must be taken because the ruby (corundum) is harder (~9) than the zoisite matrix (<6.5).

Thulite (sometimes called rosaline) is the pink massive variety of zoisite. It is usually not transparent enough to facet and large crystals are rare, but massive is used for cabachons, beads, and carvings. It sometime has green accents. Technically, much of what is called “thulite” is actually clinothulite (a variety of clinozoisite) or piemontite. The difference between zoisite/ thulite and clinozoisite/clinothulite is the crystal structure. Thulite may be called pink jade (“Wyoming Pink Jade” is thulite), and it can resemble rhodonite. The pink color is due to the presence of manganese (as is the pink color of rhodonite and rhodochrosite). Thulite is mined Norwegian Thulite. Wikimedia, courtesy Zbynek Burival at several Norwegian locales, and occurs in California, including at certain quarries in Riverside County. Local rockhounds find thulite near Ludlow, although some have questioned whether this material is actually thulite.

Reference: The Collector’s Guide to the Epidote Group, by Robert J. Lauf (Schiffer, 2008) http://www.classicgems.net/Pleochroism.htm, https://en.wikipedia.org/wiki/Pleochroism https://www.gemsociety.org/article/what-is-gemstone-pleochroism/

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DELVINGS 16643 Chicago Ave. Bellflower, CA 90706

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Regular Meeting of the Delvers Gem and Mineral Society September 13th, @ 7:00 PM at the Holy Redeemer Church, 14515 Blaine Ave., Bellflower, CA Program: we will be filling grab bags Visitors are always welcome Board Meeting (all members invited) 6:00 PM

Delvers Gem & Mineral Society, Inc. - mailing address: P.O. BOX 112, Wilmington, CA. 90748