lapidary-msg - 9/17/99 Period and SCA gemstone cutting. NOTE: See also the files: gem-sources-msg, amber-msg, jewelry-msg, pearls-msg, beads-msg, coronets-msg. ************************************************************************ NOTICE - This file is a collection of various messages having a common theme that I have collected from my reading of the various computer networks. Some messages date back to 1989, some may be as recent as yesterday. This file is part of a collection of files called Stefanšs Florilegium. These files are available on the Internet at: http://lg_photo.home.texas.net/florilegium/index.html I have done a limited amount of editing. Messages having to do with seperate topics were sometimes split into different files and sometimes extraneous information was removed. For instance, the message IDs were removed to save space and remove clutter. The comments made in these messages are not necessarily my viewpoints. I make no claims as to the accuracy of the information given by the individual authors. Please respect the time and efforts of those who have written these messages. The copyright status of these messages is unclear at this time. If information is published from these messages, please give credit to the orignator(s). Thank you, Mark S. Harris AKA: Lord Stefan li Rous RSVE60@email.sps.mot.com stefan@texas.net ************************************************************************ From: jjohns@tc3net.com Newsgroups: rec.org.sca Subject: Period lapidary techniques Date: 19 Aug 1996 17:24:05 -0700 Does anyone know of sources for period lapidary techniques besides Theophilus? His info is ok, but I'd like some alternatives to prepping rock crystal by warming it in goat's blood - you get the idea. Any more practical info would be most welcome. Thank you Alasdair MacRaibert a'dun Alasdair (Tom Johnson) jjohns@tc3net.com From: ddfr@aol.com (DDFr) Newsgroups: rec.org.sca Subject: Re: Period lapidary techniques Date: 20 Aug 1996 14:23:03 -0400 Alasdair asks: "Does anyone know of sources for period lapidary techniques besides Theophilus? His info is ok, but I'd like some alternatives to prepping rock crystal by warming it in goat's blood - you get the idea. Any more practical info would be most welcome. Thank you" 1. You are unfair to Theophilus. He also describes practical techniques for shaping and polishing stones, including the use of powdered emery, attaching the stone to a dop stick with something rather like modern dopping cement, etc. 2. Take a look also at Cellini's _Art of Goldsmithing and Sculpture_ or something close to that title. He certainly discusses "improving" stones by making colored foils to put behind them; I don't remember if there is anything on actually cutting the stones. David/Cariadoc From: Alasdair MacRaibert Newsgroups: rec.org.sca Subject: Re: Period lapidary techniques Date: 21 Aug 1996 19:18:58 -0700 In article , ddfr@aol.com says... >1. You are unfair to Theophilus. He also describes practical techniques >for shaping and polishing stones, including the use of powdered emery, >attaching the stone to a dop stick with something rather like modern >dopping cement, etc. Your Grace Cariadoc, The reference to Theophilus was made as a poor joke. When I read 'On Divers Arts', I made a joke with my lady on how they would accept carving of rock crystal by his methods at a kingdom A&S competition and whether it would be considered a science or a performing art. :-} I do intend to try his recipe for chaser's pitch and his grinding techniques. >2. Take a look also at Cellini's _Art of Goldsmithing and Sculpture_ Thank you for the reference and I will take a look at it the first chance I get. I have two other possible references if you're interested. The first comes from a Dover edition book called ' The Book Of Trades' which shows a series of wood cuts published in 1568. One of the pictures is of a gem cutter using a treadle powered rock grinder, but has no text description of methods. The other reference is more empirical. In the July 1990 edition of National Geographic, they have an article on emeralds. In that article they show a scene from modern day India and a row of bow driven rock grinders in use. I would assume that this design might be a predecessor to a treadle powered machine. There seems to be very little research or period reference on the subject of lapidary. If you should come across any other information, I would appreciate the information. Thank you, Alasdair MacRaibert/Tom Johnson From: ddfr@aol.com (DDFr) Newsgroups: rec.org.sca Subject: Re: Period lapidary techniques Date: 22 Aug 1996 22:13:42 -0400 On the subject of period lapidary techniques. All of the following is from memory; I am travelling and my library is not. 1. I believe water driven wheels are recorded at Idar-Oberstein a little before 1600. 2. Traditional Persian technology (not necessarily period) used a bow driven lathe. So does modern Indian; I have one, although I have not used it. So did classical technology, at least for gemstone carving. So I think a bow driven lathe is a fair guess for period Islamic technology. 3. One question I do not know the answer to is whether the bow driven lathe turned in one direction, with the operator raising or lowering the bow to release the tension for strokes in the opposite direction (which seems the obvious way to me), or whether it was reciprocating, which seems to be the way that the somewhat similar spring lathe works. 4. Traditional Persian technique also uses a pump drill; I have seen it done in Isfahan. I suspect that is period also, although I can't prove it. It could be used for drilling and, perhaps, engraving gemstones. 5. You might want to look at my old article on gemstones, published long ago in T.I. but also in the Miscellany that Elizabeth and I publish, which is also accessible (minus the figures) on the web. David/Cariadoc From: zarazena@io.com (Vicki Marsh) To: ansteorra@eden.com Date: Wed, 30 Oct 1996 11:00:56 -0600 (CST) Subject: Re: Good Enough? (Was Using Sigrid Eiriksdottir wrote: >I will do what I can for documentation at Laurel's prize tourney. Maybe >someone there can point me to a reference or two. Sigrid, do you have a public or university library nearby? When I live in Austin, I know there were quite a few books in their libraries about lapidary and jewelry, as I often did a lot of the research on jewelry-making for my ex-husband. Also, some of the jewelry and lapidary shops will have some books (like Dyers in Austin). Sometimes, the How-to books are a place to start, as they often have some history of the craft in the introduction. If so, look at their bibliography/references, for the next place to look. Keep looking Zara Zina From: afn03234@freenet2.afn.org (Ronald L. Charlotte) Newsgroups: rec.org.sca Subject: Re: Period Lapidary Sources... Date: 2 Nov 1996 06:01:02 GMT susankford@aol.com (SusanKFord) wrote: > Does anyone have any books or other sources on period lapidary. I can do > it with modern tools, but would like to know how it was done B>E> > (before electricity...) The one with the most useful information is _On Divers Arts_ by Theophilus (ISBN 0 486 23784 2). It's widely available in Dover reprint. Others include a smattering of info in _The Treatises of Benvenuto Cellini on Goldsmithing and Sculpture_ (ISBN 0 486 21568 7). There are a few others with small bits and pieces, and there is supposed to be a Renaissance treatise on lapidary, but I've not found it yet. -- al Thaalibi ---- An Crosaire, Trimaris Ron Charlotte -- Gainesville, FL afn03234@afn.org From: william thomas powers Subject: Re: Estrella Dust To: markh@risc.sps.mot.com (Mark S. Harris) Date: Sat, 22 Mar 1997 09:56:47 -0500 (EST) > What's a "cab"? I'm assuming it is a cap of some type. I thought at > first this was a mis-spelling but you wrote it this way several times. Sorry, a bit of jargon there---"Cab" is short for "Cabochon" which is a style of gem cutting. Instead of having flat facets the stone has a smooth dome shape---much more a pre-renaissance cut for stones. In this case the smooth domed quartz crystal provides a "window" to protect the item in the reliquery but allow it to be seen. (There are several ways of mounting them everything from soldering in a bezel to using an engraver to raise an edge. wilelm the smith Date: Mon, 22 Feb 1999 10:37:54 -0600 From: Kathleen Keeler To: sca-arts@raven.cc.ukans.edu Subject: Re: most usual semi-precious gems? Anna Troy wrote: > Well I've started to work on my circlet and I was planning on adding som > small semi-precious carbochons. Which stones are no-no's for the 14th > century? Were any more popular than the other or was it still the mish-mash > that I've seen in earlier medieval work. I was planning on blue, red and > maybe green stones depending on weither it will be 4 or more. > > Anna de Byxe Modern stones are separated by chemistry--since in Period they didn't have that tool, they mixed up some stones we distinguish: rubies and ruby-like garnets were not separable, for example. Likewise, some of the natural glasses and quartzes, when colored like emeralds (or other stones) were mistaken. If there was faceting (ie if the precious gem had a different number to faces than quartz) or hardness differences--they didn't make mistakes. See Cariadoc's Miscellany (online see SCA home page). Avoid jade (not mentioned in Period lapidaries) The Early English Text Society has a volume (#190, 1933) which reprints 7 Medieval English lapidaries. They are all based on Continental lapidaries, are derivative and repetitious. Green stones mentioned in addition to malachite include jasper, phrase, selenite, red include heliotrope, hyacinth, sard. I'd characterize it as "lore of precious stones" but it gives some sense of what stones they knew and used. I did a composite translation of the information in the lapidaries- not so much scholarly as entertaining, I understand a scholarly translation is in progress -- from the very difficult English of the originals to modern English. If you would like I can email you the text (its maybe 10 typed pages.) The original is better, but much more difficult to read and not very easily available (big university libraries and ILL). Agnes deLanvallei, Mag Mor, Calontir Date: Sat, 15 May 1999 21:34:50 -0700 From: Twcs To: sca-arts@raven.cc.ukans.edu Subject: Re: Sunstone/Iceland Spar/Andalucite When is comes to equating a classical or medieval name of a rock to a modern mineral, one needs to tread carefully. Nowadays, we usually associate one mineral name to one distinct crystalline form of an inorganic compound. For example, rhombahedral calcium carbonate is calcite, whereas orthorhombic calcium carbonate is aragonite. Aragonite is what pearls are made of, by the way. In the middle ages, however, rock names were assigned on the basis of physical properties, usually color and/or chemical action. For example, both colorless topaz (Al2SiO4(F,OH)2) and diamond would be called adamant. Similarly, the common hydrous sulfates of iron, zinc and copper could all be used to make sulfuric acid, and therefore were called green, white and blue vitriol respectively. Alum is the worst, actually. Medievally, practically every white hydroxenated or hydrous aluminum sulfate which occured naturally and made a sweet-sour astingent solution when dissolved was called and used as alum. There are over 20 modern minerals which medievally were used as alum. (So if you've ever been confused by medieval shipping records which differentiate between Egytpian or Tuscan alum, know you know why...) Unfortunately, threre's a great deal of confusion still concerning the use of gem names. Yellow topaz is also called citrine, but so is yellow quartz. Occasionally, yellow quartz is passed off as topaz. Cat's eye, a variety of crysoberyl is often confused with tiger's eye, a quartz replacement of fibrous crocidolite. There are many more examples. The ones that really get me fired up are when someone tells me about a "red sapphire" or a "blue emerald," especially in context of buying gems or jewellry. Sapphires are by definition the blue variety of corundum, and emeralds are the green variety of beryl. Red sapphires, blue emeralds and their like are often either marketting ploys or cases of outright fraud. Basically, correctly identifying a medieval rock name with a modern mineral is a mess. I find it frustrating, and I do min id professionally. I can't imagine what it must be like for folks who aren't rock geeks. I'll give those who are interested a foot up, however: if you can find a seventh or EARLIER edition of Dana's Manual of Mineralogy, you will find that each mineral entry contains a history of what is was named and by whom, including classical and medieval sources. The early editions of Dana, however, are all nineteenth century, so they're hard to find (try a university library - that's where the copy I use is located). The Hoover and Hoover commentary to Argicola's De Re Metallica is also helpful (it's included as part of their translation of Agricola, and is available from Dover books). ttfn, Twcs Date: Fri, 21 May 1999 15:57:45 -0400 From: Warren & Meredith Harmon To: sca-arts@raven.cc.ukans.edu Subject: Caro's List of Gem Books Here is my recommended list of books - your mileage, of course, will vary. Opinions expressed are only my own. I hope they help.... The Audubon Society Field Guide to North American Rocks and Minerals, Charles W Chersterman, is a good field guide for those like me who like to go digging in the field. The pictures are excellent, definitions, locations, etc. It was my first rock/mineral book, and I consider it my best book. For a specification in gems, even though it's a little on the easy side...Eyewiness Handbooks' Gemstones: The Visual Guide to More Than 130 Gemstone Varieties, by Cally Hall. ISBN 1-56458-498-4. This is the book I carry when selling gems, because it can explain to almost everyone what they are looking at...or what they may want. It's arranged by color *and* composition, which is quite handy! Unfortunately, some of the remarks are a bit generalistic for Scadians...I keep asking myself, "yeah, I know the Egyptians used fluorite to carve scarabs, but how, why, and what location did they get it from?!?" But *excellent* pictures of faceted and carved and cabbed gems, with pics of some famous gems through history. For pictures alone, most of them period...Gemstones, published by Streling Publishing Co, New York. Excellent shots of some of the more exquisite jewelry pieces through history (one of these days I *will* duplicate that Sumerian crown!!!). ISBN 0-8069-6834-6. For those with a more chemical mind...Minerals and Gemstones of the World, by G Brocardo. It's a Naturetrek Guide, ISBN 0-7153-0197-7. Each mineral has a chemical analysis, but it's written with the layman in mind (which I appreciate, even though I have a chemical background.)The charts at the bottom of each page give a quick visual of the chemical properties of each item...including clevage, hardness, color, mineral class, specific gravity, fusibility, occurrence, luster, solubility, use, preservation (which is great for display cases!) powder color, flame color, toxicity, etc. Each overleaf can be folded so you can have a side-by-side comparison with the page you're interested in. Excellent stuff! Now for those who are more interested in the metaphysical properties...Love is in the Earth: A Kaleidoscope of Crystals Updated by Melody. ISBN 0-9628190-3-4. Almost every rock, gem, and mineral known to mankind is in here, but I have some caveats: 1) It's written as if you actually know a little about mineralology, 2) You have to take one person's word for what's written - it's difficult to corroborate metaphysical info, 3) It doesn't use standardized names...black agate from one location is given a different name than black agate from another location. Of course, this ticks me off royally, but they at least attempt to use location prefixes to the names...well, sometimes.... 4) Some of these rocks you won't find outside someone's imagination. And, here's my general caveat: whether or not you believe in the metaphysical properties of rocks and minerals, please treat them as you would any other medical item. Some people *will* have allergies, and some people will *not* react as the book says. Please keep that in mind, and treat people and rocks alike with respect and caution. Okay, my lecture's over. Also, for those thinking about getting into collecting or just want more info: if yo uhave a Border's or a Barnes & Noble or a Feed & Read Bookstore or...well, okay, you get the point - go and browse through their rock & mineral section. You may find one that suits you quite well, and you get to thumb through them yourself. That's what I did, and I came up with these "gems" (heh!) on my own. But, good luck, and happy hunting! -Caro (herkimer hunting in four weeks!!!!) Date: Tue, 25 May 1999 18:04:41 -0700 (PDT) From: H B To: sca-arts@raven.cc.ukans.edu Subject: Arab Roots of Gemology In the current issue of _Gems & Gemology_, there is a book review of a new English translation of _Best Thoughts on the Best of Stones_ by Ahmad ibn Yusuf al Tifaschi (1184-1254), translated with comments by Samar Najm Abul Huda, Scarecrow Press, Lanham, MD, 1998 US$45.00. Review is excerpted here. -- Harriet "One important aspect of gemology is the history of gemstones. Unfortunately, a wealth of early works have been lost to modern gemologists, as evidenced by the number of gem references sited in Pliny's first-century encyclopedia that have disappeared without a trace. Although much of the knowledge possessed by ancient Greece and Rome was preserved by Arabic writers, for the most part such works remain inaccessible to all but the few western scholars who have learned Arabic. "This compilation offers a fascinating glimpse at ancient gemology, according to the book _Best Thoughts on the Best of Stones_, by Ahmad ibn Yusuf al Tifaschi (1184-1254). Its translation marks the first time that early Arab gemological literature has been studied by a modern Arab gemologist. Mrs. Huda is a competent translator who has endeavored to make the contents of this pioneering work easily accessible to English-speaking readers. She aimed the book at 'all readers interested in gemology, mineralogy, jewelry, history, Arab heritage, Islamic art, and the history of science.' In the reviewers' opinion, she has accomplished her goals with great success...." "...includes a glossary of gem names in English with their ancient and modern Arabic names...places al Tifaschi's work in context by describing the era in which he wrote and the nature of the Arabic literature on gems from the eighth to the 13th centuries....explains the monetary terms, weights, and measures employed at that time...." "For each gemstone, al Tifaschi briefly describes how the gem is formed; its localities, qualities, characteristics, benefits (mostly medicinal and talismanic), and prices; and, in some cases, its lapidary treatment...." reviewed by Si and Ann Frazier, Lapidary Journal Correspondents Edited by Mark S. Harris lapidary-msg