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View Full Version : Please Help! I cant pulverise Lapis Lazuli!


red81king
01-23-2015, 03:29 PM
HI! I have been on a quest to make fra angelico blue but I cant crush the lapis small enough! any help would be great, thank you.

I have been using a granite mortar and pestle. is there any other mortar and pestle someone could recommend or a mill of some kind that could handle a Mohs 5.5-6 ? or a specific product that someone else has used?

again thank you, I would really appreciate any help!

Mythrill
01-23-2015, 03:48 PM
HI! I have been on a quest to make fra angelico blue but I cant crush the lapis small enough! any help would be great, thank you.

I have been using a granite mortar and pestle. is there any other mortar and pestle someone could recommend or a mill of some kind that could handle a Mohs 5.5-6 ? or a specific product that someone else has used?

again thank you, I would really appreciate any help!

Red, you would need a very large amount of lapis to make ultramarine paint comparable to the grade of synthetic ultramarine blue, because you'll get a lot of ashes (impure ultramarine) out of the process.

If you are still interested, Lapis is soft, so you can probably break it with a piece of hard glass or granite.

Gigalot
01-23-2015, 04:03 PM
Pigment grinding is necessary. I use granite slab and agate muller. But I think, glass or porcelain slab and quartzite muller will be great. Dark minerals into granite slab can affect pigment color. These dark minerals have low hardness, 3-4 Mohs.
Grind pigment with water to a fine particle size.

yellow_oxide
01-23-2015, 05:50 PM
In this thread I showed a lapis lazuli watercolor that I made- link (http://www.wetcanvas.com/forums/showthread.php?t=1334060)
Here's the relevant images-

http://www.wetcanvas.com/Community/images/05-Nov-2013/1045312-lapislazulipigment.jpg
http://www.wetcanvas.com/Community/images/05-Nov-2013/1045312-lapislazuliwatercolor.jpg

I used a 3 pound hammer (1.361kg) and a slab of steel meant for jewelry making to make the initial breaking of the stone into powder. After that I ground it further in a steel mortar and pestle, which has been scratched a lot by some of the harder stones I've ground, seen here along with the rest of my tools from when I was making pigment from anthracite (coal) (http://www.wetcanvas.com/forums/showthread.php?t=1329654)-

http://www.wetcanvas.com/Community/images/19-Sep-2013/1045312-makinganthracite1.jpg

As has been noted already, the raw lapis lazuli stone has a lot of impurities. It's not Fra Angelico blue until after those have been removed. I never tried the process because I only had a tiny stone. If you don't remove the impurities you'll get a very weak and greyish blue, like above. If you do remove them it'll still be weaker than synthetic ultramarine, but supposedly not nearly as weak as ground but unprocessed lapis lazuli. Synthetic ultramarine with a lot of fillers might be more practical. :)

red81king
01-23-2015, 09:34 PM
Thanks Mythrill! I ll do that, I will up my quantity of lapis, I dont think I bought enough after I saw your post.

And thanks Gigalot! I was really wondering why my granite mortar was doing that. I will take your direction and change pestle mortar.

Yellow, great pics and process, I read that you found it easy to grind which I have not found to be the case. This is making me really excited, because it gives me hope after I change my tools.

Thanks, this is my first paint made from scratch, I really appreciate everyones wisdom!

karenlee
01-24-2015, 10:54 AM
Cennini wrote in a Treatise on Painting about how difficult it is to grind Lapis, due to its hardness. (His Treatise is available as a free ebook online.)

More info on Lapis & grinding from Master Pigments:

http://www.masterpigments.com/lapis-lazuli-pigments/

Note the mention of different grades of, adulterated, and fake, Lapis.

Gigalot
01-24-2015, 01:21 PM
Also, Azurite grinding process:

"This sand is then washed, and grinding in water follows. For grinding I use jar mill from high alumina ceramics with yttrium stabilized zirconium to minimize contamination. Azurite is quite soft mineral so the contamination from grinding is negligible. The solution of pigments particles of various size as the result of milling is left to settle. From 10-30 min. intervals is solution poured into different container. Settlings are collected and washed again and then left out to dry. Dried pigment is sieved and separated by particle size and color. The pigments with too big particles are grinded again."

Mythrill
01-24-2015, 01:43 PM
Cennini wrote in a Treatise on Painting about how difficult it is to grind Lapis, due to its hardness. (His Treatise is available as a free ebook online.)

More info on Lapis & grinding from Master Pigments:

http://www.masterpigments.com/lapis-lazuli-pigments/

Note the mention of different grades of, adulterated, and fake, Lapis.

Karen, honestly, I prefer the ultramarine ashes. The beautiful, grayish, low-tinting-strength color is pretty useful as a mixing and desaturating color. If I wanted a deep, pure blue, I could simply purchase synthetic ultramarine!

Mythrill
01-24-2015, 02:01 PM
In this thread I showed a lapis lazuli watercolor that I made- link (http://www.wetcanvas.com/forums/showthread.php?t=1334060)
Here's the relevant images-

http://www.wetcanvas.com/Community/images/05-Nov-2013/1045312-lapislazulipigment.jpg
http://www.wetcanvas.com/Community/images/05-Nov-2013/1045312-lapislazuliwatercolor.jpg

I used a 3 pound hammer (1.361kg) and a slab of steel meant for jewelry making to make the initial breaking of the stone into powder. After that I ground it further in a steel mortar and pestle, which has been scratched a lot by some of the harder stones I've ground, seen here along with the rest of my tools from when I was making pigment from anthracite (coal) (http://www.wetcanvas.com/forums/showthread.php?t=1329654)-

http://www.wetcanvas.com/Community/images/19-Sep-2013/1045312-makinganthracite1.jpg

As has been noted already, the raw lapis lazuli stone has a lot of impurities. It's not Fra Angelico blue until after those have been removed. I never tried the process because I only had a tiny stone. If you don't remove the impurities you'll get a very weak and greyish blue, like above. If you do remove them it'll still be weaker than synthetic ultramarine, but supposedly not nearly as weak as ground but unprocessed lapis lazuli. Synthetic ultramarine with a lot of fillers might be more practical. :)

This blue is very beautiful. It reminds me of Cerulean Blue (PB35)!

yellow_oxide
01-24-2015, 11:54 PM
I don't know if my piece of lapis lazuli was anything close to high grade (not likely, I'd be surprised if it was), but possible reasons I did not have difficulty grinding it may include it having a high percent of some impurity that's softer.

It was only a small piece, and small pieces of stone are always easier to break down than a large piece. For example, jasper is very hard and when it's a single large stone I have to hit it fairly hard many times for anything to break off at all, but once I get a few fragments off of it those don't take nearly the same amount of effort to turn into powder.

Notice that in karenlee's link there's a video, and in that video they show it first being broken to very small fragments (at 0:28) before attempting to make a powder from it. With my 3 pound hammer I break any stone into fragments at least as small if not smaller than that before I pour them into my mortar and pestle.

I don't actually know just how finely I grind stones for pigment.

red81king
01-25-2015, 07:38 PM
Great resources, thanks everyone! I wonder if anyone knows if the ceramic mill used to mill azurite can be used to mill lapis? is there a mill anyone knows of that arent a commercial mill that could be used to mill lapis (that arnt very expensive for a small project)?

I was thinking of experimenting with putting the balls from a ball mill and putting it in a inexpensive tumbler or something, then using quartzite muller and porcelain plate that Gigalot recommended.

Does anyone think that using a ball mill is a bad idea? and is really not going to get the particle size that I need.

This is an example of a small ball mill.

http://unitednuclear.com/index.php?main_page=product_info&cPath=25_72&products_id=363

red81king
01-25-2015, 07:40 PM
I am curious about the jasper. How does jasper compare to regular pigment?

yellow_oxide
01-25-2015, 08:08 PM
It's not a half bad very transparent warm earthy red that lifts easy, but I really needed to grind it finer to avoid having the larger particles that sit on top of the paper and wipe off after the water dries. I didn't grind enough of it to try it with oil. It turns out jasper is harder than the steel of my mortar and pestle. Other stones have scratched that too, but that one especially. Actually, I think that's the one that after I transferred it to my glass grinding plate the scratching sound from thousands of large particles under my glass muller was so loud that after a few minutes of mulling I stopped and everything sounded strangely muffled to me for a minute...

I don't think I really want to try grinding jasper by hand again. There's also yellow jasper that I was interested in trying, but it's probably just as hard and there's way too many things I want to do to pursue them all. Kremer has some red and green jasper already ground, though it's expensive. I don't think that was available when I made mine.

Gigalot
01-26-2015, 10:09 AM
I tried to grind jasper to a pigment powder. I is really hard stone. You can find a lot of small jasper pieces here on the sea beach in summer vacation. Actually, color of these stones are bright red (just cadmium looking red!) or quite pure yellow. I also found a few very green colored pieces. But I forgot to take these stones at home. Jasper is a very hard thing! But unfortunately, powdered jasper has less beautiful color. Powdered brick seems to be more pleasant. And not as difficult to grinding..
But green jasper has a very pleasant cool green color! Sadly, I leave it there...:crying: May be next summer I will try it again!

llawrence
01-27-2015, 03:40 AM
Good information, folks - I was going to give jasper a try, but I think I'll skip it now. Thanks!

painthog
01-29-2015, 09:30 PM
I make my own flake white ( stack white). Getting the particles fine enough is a problem. I have tried grinding with a hand muller but it does not get fine enough. Any ideas where to have pigment ground? I have about 40 lbs.
ThankX

karenlee
01-29-2015, 11:01 PM
I was curious about ball mills too (after Googling and reading about ball mills, I started getting a lot of male-oriented SPAM). Has anyone here actually used a ball mill?

Gigalot
01-30-2015, 03:33 AM
I make my own flake white ( stack white). Getting the particles fine enough is a problem. I have tried grinding with a hand muller but it does not get fine enough. Any ideas where to have pigment ground? I have about 40 lbs.
ThankX
I remembered one guy, he tried to grind 1 kg pigment on 40cm x 50cm slab. It looks like he wanted to eat 100 hot dogs at one time instead one hot dog he can eat normally. :D
Using this 16x20 inches slab, you can try to grind effectively five grams of pigment to a very fine particle size. And you need abut one hour to do that. The thickness of pigment layer on the slab must be 0,1 mm or less. Thick layer can't be milled.

red81king
01-31-2015, 10:21 AM
HAHAHAH yea, I think I m going to get a ball mill and give it a go because there are some harder rocks that I would like to grind to pigment.

Gigalot
01-31-2015, 12:23 PM
I tried to grind a small piece of Georgian red marble. It dries now:

red81king
01-31-2015, 01:37 PM
How do you find grinded marble compares to store bought calcium carbonate powder? in texture, colour, how light interacts, as a white paint (white marble)?

Gigalot
01-31-2015, 01:52 PM
How do you find grinded marble compares to store bought calcium carbonate powder? in texture, colour, how light interacts, as a white paint (white marble)?
I will try it tomorrow. I did very fine grinding, for creamy consistency reason. With water it looks like a butter, let's see what can happen with it in oil :)

karenlee
01-31-2015, 05:20 PM
red81king--If/when you do get a ball mill, be sure to start a new thread and share your experience! I am really curious about how long it takes, and how uniform the resulting grind is. Also, I wonder if it is so noisy that you have to run it in the garage for a week...

Gigalot
02-01-2015, 08:30 AM
Red marble in linseed oil. Cacao with corn syrup consistency, very creamy, but don't resists brush moving. :)

red81king
02-01-2015, 05:52 PM
Nice thanks Gigalot~!

For sure, will do Karenlee!

Gigalot
02-01-2015, 06:08 PM
After a short time it became VERY ropey!