Good news for lovers of the beautiful white stuff from Colorado called Yule Marble (yes we have beautiful white stuff that is not snow!) After being closed for 10 months the quarry is reopening under new ownership.
Read the Denver Post article.
It seems that Colorado Marble and Carrara Marble are now linked: the new owner is from Carrara, Italy!
I'm actually working on a small piece of snow white Yule Marble right now, so I was pleased to hear this news.
Showing posts with label testing stone for carving. Show all posts
Showing posts with label testing stone for carving. Show all posts
Thursday, January 13, 2011
Friday, November 12, 2010
Test for Limestone or Marble
My cousin was here recently as he drove cross country...moving from Florida to California. Since he was a geologist in a "former" life it was fun to have him help me with some of my stones.
I confess I find stones that I think are pretty and I frequently don't know what they are! What kind of sculptor is that? Truth is, I'm more interested in how they carve and what they look like...but it is good to know what it is in case I like it and want to get more!
He told me that I can do a simple test to determine if my pieces are Limestone or Marble.
Take plain vinegar and place a drop on the stone. If it "fizzes" you have Limestone or Marble.
An alternate test is to, in place of the vinegar, use muriatic acid (you can get it from a swimming pool supply store.)
Sometimes with the limestone you have to have some stone powder rather than the solid rock...I'm not sure why, but I'm the carver cousin not the scientist!
Haven't tried it yet, but I have a couple rocks that I want to run the test on. It'll be interesting to see how it works out.
I confess I find stones that I think are pretty and I frequently don't know what they are! What kind of sculptor is that? Truth is, I'm more interested in how they carve and what they look like...but it is good to know what it is in case I like it and want to get more!
He told me that I can do a simple test to determine if my pieces are Limestone or Marble.
Take plain vinegar and place a drop on the stone. If it "fizzes" you have Limestone or Marble.
An alternate test is to, in place of the vinegar, use muriatic acid (you can get it from a swimming pool supply store.)
Sometimes with the limestone you have to have some stone powder rather than the solid rock...I'm not sure why, but I'm the carver cousin not the scientist!
Haven't tried it yet, but I have a couple rocks that I want to run the test on. It'll be interesting to see how it works out.
Monday, September 15, 2008
Testing Stones for Carving, Part 4
Today's test is specifically about softness of the stone.
This is important for the beginner especially. With limited tools and experience, you want to start with soft stones.
To test for softness, it is best if you have a point or chisel and possibly a rasp with you. Before you take any tools to the stone, be sure to ask. Most reputable dealers will say okay, but you haven't bought it yet and you will be scratching it up, so I ask.
Take your rasp or file and rub it across the stone. Does the stone yield easily? Either flaking or creating a powder? That indicates it is probably a soft and workable stone.
You can also take a chisel or point and hit a small corner of the stone. If the stone chips off easily it is soft.
On the other hand, a stone that appears soft, may be too soft--or have other issues.
White marbles that have been outdoors in the weather can become "sugary". I learned this the hard way. It is a distinctly different thing than being "soft." When the rasp runs across the stone if the powder is like powdered sugar...keep testing! Take your chisel to a bit of the stone. If the stone feels like it is disintegrating, pass on that stone. It will literally dissolve while you work!
If the stone is not a white marble and you think you like it, wet a small area and run your finger nail across it. If your fingernail can scratch it, it is an extremely soft stone--in the neighborhood of soap stone. These can be beautiful stones, but the scratch very easily and so it will be more difficult to have a finished piece without any unwanted scratches.
This is important for the beginner especially. With limited tools and experience, you want to start with soft stones.
To test for softness, it is best if you have a point or chisel and possibly a rasp with you. Before you take any tools to the stone, be sure to ask. Most reputable dealers will say okay, but you haven't bought it yet and you will be scratching it up, so I ask.
Take your rasp or file and rub it across the stone. Does the stone yield easily? Either flaking or creating a powder? That indicates it is probably a soft and workable stone.
You can also take a chisel or point and hit a small corner of the stone. If the stone chips off easily it is soft.
On the other hand, a stone that appears soft, may be too soft--or have other issues.
White marbles that have been outdoors in the weather can become "sugary". I learned this the hard way. It is a distinctly different thing than being "soft." When the rasp runs across the stone if the powder is like powdered sugar...keep testing! Take your chisel to a bit of the stone. If the stone feels like it is disintegrating, pass on that stone. It will literally dissolve while you work!
If the stone is not a white marble and you think you like it, wet a small area and run your finger nail across it. If your fingernail can scratch it, it is an extremely soft stone--in the neighborhood of soap stone. These can be beautiful stones, but the scratch very easily and so it will be more difficult to have a finished piece without any unwanted scratches.
Sunday, September 14, 2008
Testing Stones for Carving, Part 3
We covered a basic visual test and then the hearing test. If your stone passed both those tests, it is ready for another visual test.
Wet the stone with water. The entire stone. Some people just squirt the stone a little, but this really just gives you an idea of the color of the stone, not the quality. So, this is not dab a little water on part of the stone and see how pretty it looks...
With the stone wet, look for any dark lines--typically thin and fairly straight.
I'm not talking about color variation like veins in marble. Look for lines that seem to go through or around the stone. This usually means there is a crack in the stone, or a layer of different material that will probably cause your beautiful stone to break into two or more pieces.
Tomorrow we'll talk about testing stones for softness!
Wet the stone with water. The entire stone. Some people just squirt the stone a little, but this really just gives you an idea of the color of the stone, not the quality. So, this is not dab a little water on part of the stone and see how pretty it looks...
With the stone wet, look for any dark lines--typically thin and fairly straight.
I'm not talking about color variation like veins in marble. Look for lines that seem to go through or around the stone. This usually means there is a crack in the stone, or a layer of different material that will probably cause your beautiful stone to break into two or more pieces.
Tomorrow we'll talk about testing stones for softness!
Saturday, September 13, 2008
Testing Stones for Carving, Part 2
Yesterday we covered the initial visual observation "test", today we will move on to a test involving a different sense--that of hearing!
Keep in mind that no test is 100%, that said, here goes.
This is the first test I was taught--I take my point and tap the stone lightly all over. Some people use a hammer, the theory is the same. Listen to the stone as you tap it. You are listening for a bright, clear sound. If you hear more of a "thud" or if it sounds kind of hollow, you don't want that stone. We call it "dead."
Try the tapping technique on several stones and listen to the differences.
This is good a time to mention that you should ALWAYS listen to your stones. Know what your stone sounds like when you start and listen to any changes that occur as you work it. You may be coming up on a hidden flaw that could destroy your piece if you ignore the sound change!
Your stones literally "talk" to you as you work. Part of your job as the sculptor is to listen.
Tomorrow we will talk about one more visual test for our stones.
Keep in mind that no test is 100%, that said, here goes.
This is the first test I was taught--I take my point and tap the stone lightly all over. Some people use a hammer, the theory is the same. Listen to the stone as you tap it. You are listening for a bright, clear sound. If you hear more of a "thud" or if it sounds kind of hollow, you don't want that stone. We call it "dead."
Try the tapping technique on several stones and listen to the differences.
This is good a time to mention that you should ALWAYS listen to your stones. Know what your stone sounds like when you start and listen to any changes that occur as you work it. You may be coming up on a hidden flaw that could destroy your piece if you ignore the sound change!
Your stones literally "talk" to you as you work. Part of your job as the sculptor is to listen.
Tomorrow we will talk about one more visual test for our stones.
Friday, September 12, 2008
Testing Stones for Carving, Part 1
If you pick up "any old stone" and try to carve it, you could be setting yourself up for more troubles and heartaches then if you take a little time and test the stone.
The first "test" is to visually inspect the stone on all sides for any imperfections. Imperfections include cracks and soft spots, veins of different materials (harder or softer than the main stone.) These flaws can lead to the stone breaking or perhaps challenging the sculptor due to the differences in tools and techniques required.
Look at all sides of the stone for obvious imperfections. Because stones are natural, there will be (naturally) imperfections. Some will be hidden inside and you won't know they are there. Others will be glaring.
Some imperfections add "personality" or "character" and you may be tempted to work around them. These imperfections include imbedded crystals and fossils, and stones with big holes or pockets in them. While these may be beautiful to look at and could possibly be worked into an awesome piece by an advanced carver, they indicate that the stone has different levels of hardness which makes carver more of a challenge.
For a beginner, it is recommended that you have as few imperfections as possible. A stone that is consistent throughout in grain and character will be much easier for you to carve.
Tomorrow in Testing Stones for Carving, Part 2 I'll teach you the first test I ever learned!
The first "test" is to visually inspect the stone on all sides for any imperfections. Imperfections include cracks and soft spots, veins of different materials (harder or softer than the main stone.) These flaws can lead to the stone breaking or perhaps challenging the sculptor due to the differences in tools and techniques required.
Look at all sides of the stone for obvious imperfections. Because stones are natural, there will be (naturally) imperfections. Some will be hidden inside and you won't know they are there. Others will be glaring.
Some imperfections add "personality" or "character" and you may be tempted to work around them. These imperfections include imbedded crystals and fossils, and stones with big holes or pockets in them. While these may be beautiful to look at and could possibly be worked into an awesome piece by an advanced carver, they indicate that the stone has different levels of hardness which makes carver more of a challenge.
For a beginner, it is recommended that you have as few imperfections as possible. A stone that is consistent throughout in grain and character will be much easier for you to carve.
Tomorrow in Testing Stones for Carving, Part 2 I'll teach you the first test I ever learned!
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