Victoria Lapidary and Mineral Society

Hints and Tips

Table of Contentsvlms logo no bg(2)

  1. Some Shop Hints we think may be of use to you
  2. Downloadable cabbing templates (members only)
  3. Abalone
  4. Working with Abalone
  5. Amber
  6. Working Amber
  7. Faceting
  8. Jade
  9. Identifying Jade
  10. Carving Fire Agate
  11. Gold Stone


Helpful Hints – from Lapidary Shop Manual – Edited by Elmer Yoder – Compiled in Electronic Form and Re-Edited By Cameron Speedie

Please feel free to distribute but acknowledge the sources – Thanks.

There will be more coming and I will index it once it is complete. There is about 60 pages and the original is very poor quality so the ol’ OCR (optical character recognition – computer looks at a page and translates it to text) is quite challenged so the human OCR has a lot to do!

Old Miner’s Rule

While a miner’s tools, equipment and personal belongings remain in or next to a digging, that is his until he relinquishes it either by removing said property or announcing that he is finished digging in that area. Furthermore, specimens or rocks cached on or near said personal property are also the property of the miner and shall not be touched or removed without his express permission. Every Rockhound should obey this rule.

Via the Geode
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Abalone

(Editor’s note – due to the near extinction of the species the harvesting of Abalone in Canada is prohibited – please use only old shells or from foreign sources)

Abalone, (Haliotis), for over 80 million years, has been grazing on algae in the selected waters of our planet earth. Eight species may be found along the West Coast of the North American continent, from Mexico to the Aleutian Islands. They are: Red Black, Corrugated, Green, Flate, White, Pinto, and Threaded.

These shells are comprised of multi-layered “Mother of Pearl” nacre, chemically similar to the Oyster. Colour bands found in the shells are a direct result of diet and genetic factors. The outer layer is protected by a covering called Peristrum, which is a transluscent shellac-like overlay.

These beautiful shells have been found all over the world in many forms. In ancient times, royalty decorated their robes and turbans with them, Stings of Abalone shell jewelry were used by the women. During the era of barter and trade, the Abalone was often used as “coin of the realm”. In many parts of the world, at archeological digs, artifacts have been found made from these shells. Today, many forms of jewelry, from formal to baroque, are designed with the unique characteristics and beauty of the Abalone utilized to the fullest.

Many steps are used in the preparation of the shell until its final lustrous beauty is brought to life in the creation of fine jewelry.
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Working with Abalone

(Editor’s note – Abalone is extremely toxic if worked dry. Do not ever work this material unless the piece is under a steady stream of water. If you feel the least bit nauseous even when working it wet – stop immediately and get plenty of fresh air. )

Starting with the raw shell, it must first be soaked in a chemical to rid it of algae and parasitic crustations. It is scrubbed, dried, sandblasted, before it is ready for cutting. Rough shapes are formed by saw, drill, and dremel tools using diamond edged tools. This work should be done under water, with a worker wearing a respirators, plus fans blowing for ventilation to protect the workers from Silicosis, due to the dust of Calcium Carbonate from the shells.

After the cutting operations are completed, the shell parts can be placed in a tumbler for 24 to 72 hours with three changes of grit. The shell is then washed, and buffed to a high gloss finish. This last operation can be done either mechanically or by hand. The shell should now be a beautiful creation of vivid colour worthy of any jewelry setting.

All that is left now is the imagination of the craftsman. The shell can be drilled for jump rings, epoxied for any glued style, or prong set for special effects. Completion of any of these operations assures the individual of the finest in Abalone jewelry.

The world’s population has for years, gorged itself on these delectable Gastropods (Editor’s note – if you enjoy fish flavored shoe leather ; ) ), thus over-harvesting their reproductive capacity. The Sea Otter also includes Abalone as a main part of his diet, and that also reduces the reproduction. Our federal government has stepped in and placed an “Endangered Species” label on the Abalone for these reasons. Quantity limits as well as size limits have been placed on the harvesting of them. Thus, the Abalone has become more valuable, both as a food source and a jewelry source.

From the Ultralite Co. Inc. via Chips and Tips
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Amber – re-constituted

‘Ambroid’ was the tern used by the Europeans for amber that was pressed or reconstructed by fusing small pieces of amber with the use of heat and pressure.

The process was quite simple. Pieces were scraped and cleaned to remove dirt and weathered areas and impurities. The amber was then placed in a deep steel tray with a perforated partition. The container and the amber pieces were then subjected to heat to about 200 to 250 degrees centigrade. The tray was, also subjected to an hydraulic pressure of about 50,000 pounds per square inch. This forces the melted mass through the perforated partition and thereby mixes it and also forces it into molds where it cools and solidifies.

Amber will melt at a temperature of 170 – 190 degrees centigrade, and then exhibits a rubber-like consistency without disintegrating so it should be possible to melt and press a mixture of amber chips without destroying the amber. Amber will burn so be careful if you attempt this!

Early pressed amber had one major drawback – it became cloudy with age. Ambroid does however have an advantage as it is harder than natural amber.
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Working amber

Amber can be worked very easily. It can be filed to shape and then sanded with an aluminum oxide paper of finer and finer grades, (200,400, and 600 grit) until a polish step is necessary. Amber can be polished by the use of: (1) tripoli with oil; (2) aluminum oxide; (3) tin oxide;(4) Linde A; (5) rouge, applied dry.

Dip the amber piece into the lubricant (oil or water) and then dip the piece: into the polishing compound then rub vigorously on a smooth surface such as a leather strop, or a chamois attached to a hard board. The people in Europe and Mexico used wood ashes as a. polishing agent.
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Faceting

Amber can also be faceted if the lap speed is reduced. Suggested cut-ting angles are:

Cutting angles Cutting lap Cutting speed

Culet – 43 degrees Fine – extra fine 100 RPM

Crown – 42 degrees

Polishing

Lap – wax

speed – normal

agent – Linde A

Polybern – Amber in plastic

Amber can also be embedded into plastics or resins to make beads or ornaments. Commercial plastic resins are available – simply follow their casting procedures.

from Coalmont / Blakeburn via The Geode
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Jade

Lapidaries and jewelers should constantly attempt to call gemstones and rough material by their correct name. Jade has many other stones named after it, as any material. The confusion as to what jade is, has been compounded by this deceptive practice.

Amazon jade is adventurine..

American jade is a rock – a mixture of idocrase and grossular.

Australian jade is chrysophrase.

Colorado jade is green microcline.

Flukien, Manchurian, and Honan jade are all soapstone.

Indian jade is adventurine.

Jadite is pure jade. (editor’s note ? – not sure what he means)

Jasper jade is green jasper.

Korean jade is bowenite, a hard variety of serpentine. (Mexican jade is green dyed marble or calcite.

Oregon jade is a dark green jasper.

Silver Peak jade is malachite.

Transvall jade is a massive variety of green grossular garnet.

Real jade such as BC jade, Alaska or Yukon jade are truly nephrite jade:

Nephrite Hardness 6-61/2 S.G. 2.95 R.I. 1.6 1.63

Jadeite Hardness 61/2-7 S.G. 3.3 R.I. 1.66 – 1.68

 

Possibly more information (some true, some false) has been written regarding the polishing of jade than all other lapidary materials combined. And so, one concludes that jade is difficult to polish. The answer is “Yes” and “no”. Let us consider the mineral itself. There are three separate and distinct minerals that are known under the general term jade: Nephrite, Jadeite, and Chloromelanite. Nephrite is the one found in BC, Alaska, and Wyoming. This is the one we shall consider here.

Let us first consider the nature of these rock-forming minerals. They are described as being fibrous, which simply means that structurally, they are a mass or network of tiny fibrous hair-like crystals, much like straws in a straw stack. They are so fine in nephrite that they cannot be seen even with a powerful magnifier. A peculiarity about crystals is that they are generally softer parallel to the crystal growth, and harder across the crystal. It is just this simple characteristic that creates all the difficulty in applying a polish, if one uses the same procedure as for example, agate. However, provided one has the proper equipment and uses it in the proper manner, nephrite jade is easy to polish. And now for the job!

Proper sanding is of vital importance. Improper sanding mainly through use of unsuitable equipment and technique, is the greatest cause of difficulty.

We will assume that you have your cab ground to shape, and coarse-sanded on a disc or drum, using 120 or 220 grit. The 220 is slower, but otherwise it matters little which is used. Recommended sanding speed is about 1000 RPM for a ten-inch disc. And not too much pressure, for more reasons than one. We have all read of using a well worn sanding cloth for the final touches. This is O.K. for quartz minerals, but in my experience does not apply for jade, nor any other fibrous material. Crystalline Rhodonite, for example. It is obvious that sanding will tend to wear away the fibres parallel to the direction of rotation of the sander at a faster rate than the fibres at right angles. This pesky behavior is called undercutting, and must be avoided. If we use the well worn technique, we will probably decide that the old cloth isn’t doing much,.. so a little extra pressure is added. What happens? In the first place, the stone is liable to be burned, creating nasty white spots, which, of course, must then be ground out. And that cab looks a little on the thin side already: But what is just as bad, if not worse, the sander (which has a small amount of resiliency) will be forced to plow out the parallel fibres and leave the cross-fibres already mentioned. What do we have now? Just plain orange peel. The obvious remedy is to use a sharp sander. No matter what number grit we are using. This will have a planing action which will remove material without undue pressure. After our cab has achieved a fine satin-like appearance all over, we may proceed to the fine sanding operation. But first, scrub the stone and dop stick to remove all traces of coarse grit. And make sure there is no grit (let’s call it dust) anywhere- near the fine sander. 320 grit will be found quite satisfactory (and fine enough) for the final sanding. But here again, it must be new, sharp grit.

Do not depend on this 320 to remove much material. As stated before, have a nice satin finish before leaving the coarse sander. The 520 grit will soon produce a mirror-like surface that ‘night easily pass for a polish. Any areas that appear to have a “frosty” look are not sanded enough, and this frost must be removed. Actually, They are areas of small pits and depressions that are filled with sanding debris.

We now have a semi-polished stone. This must again be very thoroughly scrubbed, particularly behind the stone where the dopping wax is located. And doubly important, this time, all dust must be removed from anywhere near the polisher. For polishing jade, we find that heavy harness leather, at least an eighth inch Thick is most suitable. Do not try to use light leather. A piece of felt floor covering makes a good cushion behind the leather. Chrome oxide is the most satisfactory polishing agent. Slow speed, not Over 350 RPM for a ten-inch disc works best. Quite’ heavy pressure is generally required. Particularly for flat surfaces. And just enough water to keep the leather moist, applied with the chrome oxide in the form of a thin cream. Considerable pull will be felt as the leather dries cut. It is only while this pull or drag is felt, that actual polishing takes place.

via The Laphound News
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Identifying jade

1. If you chip the edge of a suspected specimen and it sparkles or glitters, it’s not jade.

2. If you can scratch it with a knife blade, it’s not jade.

3.It should be much heavier than a common rock of similar size.

4.Tap The specimen lightly with the point of your pick. If a small moon-shaped fracture shows up, it is agate or jasper, but not jade.

If it is jade, it will have a smooth, waxy, almost greasy, look and feel.

 

The Puget Sounder via The Rock Licker
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Carving Fire Agate

The most important thing to remember before you even start is to select a good piece to work with. Carving is a very demanding aspect of the lapidary field. It requires patience, patience, patience. It is a time consuming venture into the unknown. You do not want to waste days or weeks working on an inferior piece of material. True, There is a chance you may destroy a beautiful layer of fire, but if this happens then go deeper and you may uncover another layer that is just as sensational. Keep this in mind and don’t be afraid to dive in.

The first step is to remove the layer of chalcedony that usually adorns the top of the fire layer. Remove this carefully. If the layer is thick you may wish to use a trim saw to partially remove some of the excess. Be very careful about trying to remove too much in This manner as you may be removing some fire also. I always leave some chalcedony – for two reasons. Number one is because you may wish to incorporate a portion of the chalcedony in the design. Number two is that the fire agate is botryoidal and part of the fire “bubbles” could extend up into the chalcedony. After removing as much as possible or advisable, be sure to clean the stone thoroughly. Just as in any other cutting process, all oil or coolant should be removed.

The next step is to go to the hand tools. I use a Foredom Flex Shaft with a flexible handpiece #8AD. There are several very good motors and handpieces on the market, but in this article I am giving you the machines, tools and equipment that I work with. Always keep in mind that I am not endorsing any particular product.

Before starting the actual grinding with your handpiece, you must have bowl or container of water beside your workspace. The stone must be worked wet at all times. I like a lot of extra work but my bowl is low and I use a block of styrofoam approximately 5″ X 5″ X 3″ high as a support and steadying device. By resting my hands at the “heel” area above the wrist (on the block) it is a very simple matter to swing my hand over to the bowl of water and back to the business of grinding. This is my way of doing it, anything that feels right for you is the way to go. Just keep that stone wet.

You must get down to the brown material which encompasses the fire layers. This is accomplished by using a heavy duty diamond sintered wheel. My preference is a 1/2″ wheel. Through experience I have found the sintered wheels do an excellent job and do not have to be replaced as other types. I would also like to note at this point another reason I use diamond sintered wheels is because they work much faster than the silicon carbide or aluminum oxide points. As a beginner you can use the above mentioned points and turn out a beautifully finished product, it will just take longer. If you see that carving is for you, something you really enjoy doing, invest in the diamond points. It is an excellent investment.

You do not need a wide variety of points to begin with. I started with a 1/2″ heavy duty wheel; 1 diamond thin disc; 2 tapered cylinders – round head (1 small, 1 larger); 1 cone; 1 barrel; 2 flames (1 small, 1 larger). Your inventory can be added to as you progress, but the above will give you a good start.

Once you get to the brown material, remove the heavy duty wheel and insert a barrel point in your handpiece. The barrel point is a versatile point – it clears larger areas in a hurry, but can be used to perform other jobs also. At this point let me suggest you take just any piece of agate and experiment with the various points and wheels. This way you can familiarize yourself with each one and learn its capabilities. Never force your points – use an easy stroke let the point or wheel do the work.

This is where the fun begins You have now reached the first real stage of wonderful things to come. You should be able to see the contour of the fire lines. Study the piece carefully and try to see what the stone contains. It will tell you what you are going to carve from it. There is something waiting to be born and you can give it life.

Take a fine- tipped felt point pen or an aluminum point or whatever you use to outline a cabochon and outline what you see. In other words, make a drawing on the stone of what you are going to carve. When you have outlined all of the main features, study it again. If there are any corrections to be made, now is the time to do it. Using your thin disc or separating disc, follow your “drawing” lines. You will be cutting into the stone, so keep that stone wet. As you cut these initial grooves you will find it easy to keep your cutting area wet as the water will follow the groove. It may be necessary to go back over This cutting procedure again in order to get the grooves as deep as you want them. it is better to cut thin grooves to start with. Remember, you have a great deal of grinding and sanding to do to actually shape your carving, so allow for this.

Once the initial outline had been cut, you can go on to the business of rounding or detailing your carving. If you recall, I suggested earlier you take a rough piece of agate, of any kind, and practice using each point to familiarize yourself with its capabilities. You now want to make your carving as three-dimensional as possible, giving it a life-like appearance. This will not happen overnight. You will have to work and rework areas until you have achieved the right look for your particular piece. Use caution at all times. You do not want to grind or sand too close to the fire or you will end up erasing the fire. Fire layers are so thin that they will just disappear before your eyes, so leave enough of the brown layer above the fire to allow for the six to seven polishing stages you will be using.

Work your carving with your various points until you achieve a fairly smooth surface. Now you are ready for The polishing stage. I use diamond compound in a syringe dispenser, usually 2 grams each, with mesh equivalent of 325; 600; 1,200; 14,000 and 50,000. Diamond compound will go a long way if used properly. I mix a small amount of compound, about the site of a wooden match head, with one drop of crystalube and make a paste of this. I then take a round toothpick and apply this pasta over the surface of the carving.

Before going any further, let me explain the typo of point I use in my flex tool to achieve a brilliant polish. I turn my own wooden points, in various sizes.

They are turned to fit the collet of my handpiece. I go to the lumber yard and buy a 3 foot length of 1/4″ doweling (the hardest wood available), then cut it into 2 inch lengths. One inch for the shaft and one inch for the point. The shaft is turned to 1/8 inch diameter, the point being + inch (or less) at the base and shaped to a rounded point or cone shaped point. I also use the rounded toothpicks for areas the larger points can’t reach. Wooden points are marvelous tools for polishing. They absorb the diamond compound and do not heat the stone as other agents do.

Contamination is one thing that is to be avoided when using diamond compound. Just a minute grain of a courser compound can cause scratches on the surfaces that are not readily visible until you reach the final polishing stage. It may well be necessary for you to go back and start from scratch, which is something you want to avoid.After each stage of polishing, your carving must be completely cleaned of all the compound just used. This is the sane precaution you used when tumbling stones, and for the same reason.

Start the polishing process with the 325 mesh and proceed with each of the next five mesh compounds following the above instruction. Remember, a fresh point must be used with each grade of compound. in order to avoid confusion on which point I had used for which compound, I marked the shaft with a #1 through #6 and stored my used points by sticking the shaft end into a large block of styrofoam, point up. This insures that they do not rub together or contaminate each other.

The polishing process must not be hurried. Take plenty of time with each compound In order to insure a good polish. There are times when I am not completely satisfied with the final polish, so to give it a higher luster I will go to a cerium oxide or tin oxide. I soak the wooden point for a few seconds before applying the oxide. Remember, your stone will heat rapidly with oxides, so keep the stone wet during this operation. If you overheat the stone it will “scorch” the surface and you really have a problem. There again caution and patience apply.

After reading these two articles you may think “it’s not worth it”. I have purposely stressed caution and patience because I want you to achieve good results on your first effort. Believe. me, it will all become “second nature” after a few experiments and will become an exciting and rewarding experience. It’s like riding a bicycle, once you have learned, it becomes automatic. The joy or seeing a carving come to life far outweighs the time and effort put into a piece.

By Lou Thorpe — via Ore-Bits
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Gold stone

Goldstone is not a natural stone but man made. It can have a very beautiful effect if oriented properly. The same system is used as described for tigereye with a few possible exceptions. Do mark it under a good light for direction of sawcut. However do not rely on your marks too heavily.

Mica flakes provide the chatoyancy and they are arranged within the piece in parallel form but there are also flowlines probably made by stirring the molten mixture and they are seldom straight. They may and often do change from slab to slab. Therefore special care has to be taken. A method to use in sawing slabs is to check each one as it is cut before the next is done. As soon as one begins to get a recognizable variation in chatoyancy take the piece out of the saw vise and re-orient it before proceeding. occasionally in bad pieces this may have to be done after every second slab, though. just as occasionally one may saw the whole piece without having to re-orient.. If one doesn’t check after each slab one could wind up with the majority of slabs being improperly oriented which in Goldstone is a disaster. So the important point is to check often as sawing progresses to avoid disappointments later. Better yet is to watch for the flaw lines of the material when buying; If violent curvature exists in them the possibility of having good orientation is virtually impossible.

via The Canadian Rockhound
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