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The Stone Corner

Stone Queries: Carving Marble - March/Apr 2008

As an alabaster/limestone kind of person, I find the prospect of carving marble intriguing but a bit intimidating. Would I need a different set of tools, carbide or diamond for example, to work in marble?


The first piece I ever carved was in marble. Being uninformed (ignorant, or at least uninitiated) I used a ball peen hammer, cold chisel, wood rasp, metal file, and wet & dry sandpaper. I am still pleased with the result. Many of the tools you now use in softer stone are also usable in marble. Admittedly there are softer marbles and harder marbles but steel tools are often quite satisfactory, especially points, claws, and chisels, in both hand and air hammer carving. Because of its brittleness, carbide tips on those tools are ground to a blunter cutting edge and must be held at a steeper angle to the stone surface than steel tools. I prefer the feel of the cutting action of the sharper steel edges in marble, but this is only a personal preference not a commandment. You will probably learn to use the point and claw closer to the final surface than you may have in alabaster since most marble won't bruise as easily as alabaster.


Steel rasps, rifflers and files are also very serviceable although they will wear a bit faster than carbide or diamond. Even so I have a small steel file that shows little wear after several years of being used on marble. I fear breaking or losing it because I have yet to find another like it. One place I would recommend carbide or diamond is in bits for die grinders or handpieces. They cost more than steel but they last much longer. At some point you may find an angle grinder with a diamond blade very useful for roughing out. I use one at some stage of carving nearly every piece I do but often I also use a hammer and point for waste removal, not for any esthetic or philosophical reasons but because it is very rapid way to move stone. But I do like an angle grinder for sanding and polishing broad surfaces.


Work first with lighter marbles, white or gray. Black, fine-grained marbles such as Belgian black are quite brittle and best worked with abrasives. Remember too that the term "marble" covers a multitude of stone types, some of which are difficult to work even with diamond tools.


You will probably have to give up your nail files, emery boards, and various sharp thingies that are great for detail work in softer stone but don't be intimidated, or lured, by all of the specialized tools available. There is always another nifty tool out there and angle grinder envy can be insidious. On the other hand, have you seen the new tool that...

Stone Corner - Alabaster Nov/Dec 2007

Ed: this column on alabaster was last printed in Sculpture NorthWest in the March/April, 2001 issue. Bill Laprade (say it La Prawd) lives in Seattle and is a stone sculptor and a geologist. As a past NWSSA Board Officer for four years, he helped shape the policies for many Association procedures and Symposia. Bill is graciously permitting us to reprint a few of his useful stone columns and we hope you benefit from his expertise and knowledge.


Waxy, multi-colored alabaster has been the stone of choice for artists and artisans for millennia. It not only serves as the source of beautiful sculptures, but historically it has provided utilitarian objects such as jars and casks. It was prized by the Assyrians and the Egyptians for its beauty. One of its most handsome and unique characteristics is its ability to pass light; imagine, a stone through which light can be seen. While we sculptors use it for carving, alabaster's cousin, gypsum, is around us most everywhere we go and is handy on all our workshop shelves.



Alabaster is one of several forms of gypsum, and it is both a mineral and a sedimentary rock.  It is hydrated calcium sulfate, CaSO4' H2O that is found in many places throughout the world. It is a sedimentary evaporated deposit that precipitates from the evaporation of saline water. The ideal conditions for its formation are (1) a restricted arm of the sea, (2) intense evaporation, (3) replenishment by normal sea water and (4) gradual sinking of the basin.


It is unknown whether gypsum is deposited directly in its hydrated form or if it evolves from other minerals. Gypsum may be transformed from anhydrite (CaSO4), as this anhydrous version takes on water when exposed to the elements near the earth's surface. In support of this hypothesis, gypsum is only found in the upper 100 to 300 feet of the earth’s crust, where the weathering process has affected the rock. Alabaster is the massive, fine-grained crystalline variety of gypsum. Other rocks that are commonly found in association with gypsum deposits are halite (salt), calcite, dolomite, clay and limonite.


Alabaster has a hardness of 2. It comes in a wide range of colors: white, translucent, gray, yellow, brown, orange, pink, green, raspberry, strawberry and variegated shades. The colors are the results of impurities such as organics, clay and iron oxide (rust), among others. Green alabaster may take its coloring from smectite clay that is commonly found in the same depositional environment. Commercially mined alabaster is bedded, with strata ranging from 3 to more than 100 feet thick. Products for which gypsum is used are fertilizer, concrete additive to retard setting time, a yeast growing nutrient, a flux for pottery, plaster of Paris, patching compounds, stucco and drywall.


Some of the locales where alabaster is found in the world are Utah, Colorado, California, Arizona, New Mexico, Florida, Tuscany (Italy), Iran and Pakistan. Much of the alabaster that finds its way to the Pacific Northwest is from Utah and Colorado.



Most of the alabaster quarried in southern Utah is very close to the ground surface. Only a few inches to a few feet of overburden are removed by a bulldozer to expose the stone. Because of the high elevation and rough winters, the work is carried out during long work days for about five months in the summer. The quarry areas are normally inaccessible during the winter.


Deposits of alabaster in southern Utah are layered in strata ranging from a few inches to four feet thick. In some quarries the stone breaks out in round or oval boulders that average two to three feet in diameter. The most common methods of removing the stone are a bulldozer and the use of a hand-held drill. The drill holes are closely spaced and then shims and wedges are used to break the stone into desired sizes. At some quarries, light blasting is used to loosen the stone. Experienced quarry operators check the stone for inclusions and fractures before breaking it into smaller pieces and displaying it for sale.


Working Alabaster

Alabaster is well known as a stone for teaching, because it is soft, carves easily with hand tools, and if you are fortunate, does not contain big surprises. The hardness (or softness) of 2 is conducive to easy removal of stock and yet alabaster has the ability to hold detail in the manner of many harder stones. Unlike another soft stone, soapstone, that commonly changes hardness, has hidden fractures and spalls unexpectedly; alabaster is generally uniform in hardness and contains fewer veins or fractures. Some of the flaws that do arise are veins or voids filled with clay. Fortunately these mud veins or pockets are not laterally continuous, so that although the design of a sculpture piece may have to be altered, it is uncommon that the stone is a loss. Unfortunately, the mud veins or pockets are not normally evident on the outside of the stone. While cracks or fractures in alabaster are not common, there has been some experience that Colorado pink may contain more hidden fractures than other varieties of this stone.


Alabaster can be worked easily with hand or power tools. Roughing of the form is accomplished with points, followed by toothed and flat chisels. Chisels bruise this stone easily, so inspect the surface vary carefully as you start to refine the piece with rasps and sandpaper. Rasps of different roughness or die grinders (with a jet of water to keep the dust down) are then used to impart the details of the piece. The degree to which sanding is taken is a personal decision of the artist. Some prefer to stop at 600 grit, which gives a "soft" finish, whereas others go to 1200 or 1800 grit, which imparts a bright polish. Akemi polishing fluid (stone sealer) #10-2012 or floor wax can also be used to bring out an even brighter sheen. At least three rounds of wax-and-polish are necessary to bring out a good shine.


Because of its softness and susceptibility to the natural elements, alabaster is an indoor stone. Left out-doors, moisture and freeze-thaw would soon soften the surface of the stone and ruin any details in a few years. This may be one of the reasons that the price of an alabaster piece is limited, in comparison with the harder stones.


And remember!!  Keep your goggles and masks on. The dust is very fine grained and keep in mind that it is the same mineral that is used to make plaster of Paris, spackling compound and other quick-setting fillers. Don't let it set up in your body.



Artists Meredith Earls of Seattle and the late Neil Gemmill of Kirkland generously shared their knowledge and expertise of alabaster with us. Thanks to Evelyn Dettamanti of Cedar Memorials and South-west Stone of Cedar City, Utah for information regarding the mining of alabaster in southern Utah.

Stone Queries: Stone Tapping - Sept/Oct 2007

Ed: Ron Geitgey (pronounce it GET chee) is a long-time member of NWSSA, was a professional geologist for 40 years and is a talented sculptor and photographer. In 2002 and 2003 the Journal ran an informative series entitled “Stone Queries” in which Ron answered questions that the membership had about stone. We hope that you who remember the series appreciate the review and that you newcomers will find his breadth of knowledge and practical advice helpful. Ron tells us that he is once again willing to answer any questions relating to stone that you want to ask him. Remember that the only foolish question is the one you don’t ask, so take advantage of this fount of information and send your questions to Ron Geitgey at This email address is being protected from spambots. You need JavaScript enabled to view it.


I have noticed people choosing stone to carve by tapping the stone and listening.  What are they doing?


Tapping the stone is an attempt to determine if the stone has any fractures. Some stones go thud, some ring, and some buzz or sound “odd.” Supposedly, a stone that rings has no fractures. Based on many years of experience as a stone carver and even more as a geologist collecting samples in the field, I consider the method unreliable, or at least one to use with caution. The presence or absence of fractures is only one of many factors that may affect the tonal qualities of stone.


Ringing is not necessarily dependent on stone type. Alabaster, some Soapstones, limestones, travertines, and sandstones may ring, or not, and be completely fracture free. Other stone, including marble, may ring nicely and still fracture during carving. In general, more brittle stones ring better; black marble, flint and obsidian are extreme examples.


The shape and means of support strongly affect ringing. A shapeless lump of stone is unlikely to ring while a thin bar or slab of the same stone may ring clearly. A stone lying on the ground or held in hand may not ring because its vibration is damped or muffled by the ground or the grip. A stone suspended by wire or rope, or one resting on narrow supports can vibrate much more freely. (So can one struck while being tossed in the air but that approach has obvious limits and hazards.) Suspended and supported stones have been used as musical instruments for millennia as gongs and xylophones, or more correctly, “lithophones.”


Finally, ringing can depend on the striking tool. A loosely held point or chisel can generate a clear tone but it’s not the stone that’s ringing.


So where does that leave us? Use a hammer, tap lightly, and be aware of shape and support. Test many pieces of stone to learn its typical sound, and listen for an abnormal sound or buzz. Of course you have learned something if the stone splits when you tap it. And accept the fact that stone is a natural material with natural variations. It is not a medium for those who don’t deal well with surprises.

Eight Easy Steps to Polishing Basalt - Jan/Feb 2004

Many carvers are intimidated by the difficulty of sanding and polishing basalt. This is entirely unnecessary. Basalt is in fact very easy to finish if you follow these eight easy steps. Soon you too will discover that deep space, raven’s wing glow within your own dark and crusty igneous chunks.

1. Prepare the work site environment. A comfortable work environment is essential to polishing basalt. Take your tools and stone to your favorite sandy beach where the temperature holds at a steady seventy degrees. Plane tickets may be necessary. If customs officials ask what that dense dark lump is just tell them it is depleted uranium 238, they seem to be comfortable with that. (Do not ever tell a customs official that you are an artist). Burn sage or incense and ask a local shaman or priestess to do a purification ritual for you.


2. Play music. Music is helpful in polishing basalt; not only does it distract you from the tedium of your inner dialogue (“damn scratch, damn scratch. Gwyneth is pregnant? Damn. This piece has to be delivered tomorrow etc. etc...), but it has also been clearly shown that specific sound wave patterns are able to ‘loosen’ the molecular structure of basalt. Are the large crystalline fracture patterns born of the cries of pterodactyls flying overhead?


3. Develop patience. Polishing basalt is similar to raising a teenager; they respond unpredictably from day to day and require long term persistence and love. If you do not have a teenager, get one or borrow one. Many will be enthusiastic about visiting you if tell them you will let them polish the basalt.


4. Achieve non-attachment. Getting a good polish on basalt is like attaining enlightenment. Both require a ‘letting-go’ or non-attachment to the goal. Many of my basalt polishing friends are accomplished meditators and have found that basalt polishing is relatively effortless once they have attained enlightenment.


5. Develop good hand-eye coordination. Many experienced basalt polishers were once involved in slightly less challenging careers like neurosurgery or classical violinist or pianist. Consider taking up hobbies like these to prepare your hands and eyes for basalt carving.


6. Maintain flexibility and strength. There are many yogic poses that are useful for the basalt polisher. The Twisted Crane is particularly useful for the strengthening and stretching of lower back muscles. Yogic historians believe this pose was developed by the stone carvers of the Mahabaliparam temples in 7th century India. It is interesting to note that a very similar pose can be found in the Egyptian fresco at the tomb of Nakht in Thebes (c.1450 B.C.). In these images the carvers are shown holding tapered conical blocks that look suspiciously like silicon carbide cup wheels.


7. Experiment. Imagine that you are a witch or wizard on the cutting edge of an alchemical discovery. There are many esoteric pastes and powders that have been used over time to assist in polishing and buffing basalt. These recipes tend to be personal, but I will list for you some of the ingredients that are better known: blood (source?), beer, sweat, chocolate, tears, Turkish coffee, garlic paste, bodily fluids (take your pick), the excrement of the Mayan Quirigua bird, eyeball of Newt, dragon scales, etc. Try your experiments on test pieces first.


8. Finally. Don’t be afraid to ask for help. There are probably many experienced basalt polishers in your neighborhood that would be happy to help you. They tend to be shy, though. If you slowly drive around your neighborhood in your flatbed with a three or four ton chunk of pristine columnar basalt in back, the basalt carvers will come to you. If anyone comes up to you and asks “Is that a rock?” they are probably not a skilled basalt polisher. As you can see, it is really quite simple to polish basalt. A little preparation goes a long way. In the next issue I may share with you a simple design I have used for making my own water jet cutting system out of vacuum cleaner parts, duct tape and military surplus artillery components.

Stone Queries - Jan/Feb 2004

Q: I have seen the term “freestone” used in describing Gothic sculpture.  What is freestone?

A: Freestone means stone that is uniform in all directions, that is, stone which carves uniformly in all directions, exhibits no tendency to break preferentially, and has uniform structural properties. Originally the name was used for limestones quarried in England and France. These stones’ working properties made possible the detailed sculpture and delicate traceries of Gothic cathedrals. Later the term was also applied to fine-grained, massive sandstones that had similar carving characteristics. Medieval stoneworkers skilled in working these materials became known as freestone masons, a term which many scholars believe was the basis for the name Freemasons.

Sedimentary rocks such as sandstone and limestone typically are layered or bedded, indicating slight interruptions or variations in deposition. The thickness of individual beds may be from only fractions of an inch up to many feet.  Freestone is a very thick bed, indicating continuous deposition over an extended period of time for limestone, or a single episode of very rapid accumulation for sandstone. A freestone bed often has thinner beds above and below it.

The carving benefits of freestone are obvious. You don’t have to worry about directional breakage. In architectural uses (as well as sculpture) it is customary to place stone with the bedding horizontal. This minimizes water infiltration along the bedding and utilizes the stone’s strongest direction for load bearing. There are exceptions. Bedding may be placed vertically when there are strong compressional forces from the sides, such as a keystone in an arch. Using freestone simplified addressing all of these concerns, demanded less skill of the quarrier (although perhaps not of the mason), and wasted less stone.

More recently, “freestone” has been used for any uniform rock, regardless of its origin or composition. But often freestone is a matter of perception. Few stones whether igneous, sedimentary, or metamorphic are truly structureless. I have a friend who has done stone restoration work on centuries-old buildings in Europe. He has noted many instances where, after several hundred years of weathering, supposed freestone blocks now show subtle bedding, sometimes oriented to the detriment of the structure. On the other hand if I am carving what now behaves as freestone I’m not worrying that posterity and a few centuries may prove otherwise.