Following images from Bonham’s 2014 auction, The Feng Wen Tang Collection of Early Chinese Ceramics

The best resource I’ve found about color in Chinese glazes is Nigel Wood’s Chinese Glazes.  Chapter 8, Iron in Chinese Glazes, covers iron in detail, while celadons are covered throughout the book.

There’s a great range of colour in Chinese celadons.  In traditional celadons, color is mostly the result of materials containing naturally-occurring iron being fired in a reduction atmosphere, with the color modified by the balance of other oxides in the glaze as well as the underlying clay body.  Relatively small amounts of titania, manganese, copper and even cobalt can affect the color in significant ways.  Ancient kilns like Yue, Hutian, Longquan, and Yaozhou became associated with certain colors and qualities of celadon, as the materials used at those kiln sites naturally contained particular blends of oxides.  In Jingdezhen, celadon glazes seem to have evolved from fairly simple geographically specific material-based recipes (e.g. 10 parts glaze stone from Yaoli, 1 part glaze ash from Leping) to extremely refined and intentional recipes with similar base glazes that incorporate additional materials for their specific ability to modify color.  This lead to glazes named not just for kiln sites but also specific colors and qualities:   天青 （sky blue with a small < .2% addition of cobalt），豆青（”bean” celadon pure green iron celadon），影青（”shadow” lake-green)，粉青，玉青 (jade celadon)，冬青 (winter green)，鸭蛋青 (bright duck-egg green), just to name a few.

But celadons in the Song dynasty were mostly restricted to local materials.  Thus if your local clay and glaze stone contained only trace amounts of titania and low amounts of iron (such as in towns near Jingdezhen), then you could produce the famously pure blueish-green qingbai glazes.  While if you were in the Northern Yaozhou kilns where materials naturally contained more titania, your celadons would tend towards olive-green.  (These are greatly over-simplified and generalized statements.  Regarding Yaozhou celadons, in Chinese Glazes, Chapter 6, The Stonewares of North China, Woods also mentions the blueish-grey glazes of Yaozhou, as well as the possible influence of coal firing on the color of Yaozhou celadons.)

For me, part of the beauty of Chinese ceramics is the ability of those ancient potters to reveal the beauty of their local materials, and how the resulting aesthetic of each kiln’s wares was in large part driven by the nature of those materials.

Of course, these days most of us make glazes by blending various “standardized” materials, with color variations resulting from additional coloring oxides.

The following test is a simple biaxial blend showing the influence of iron and titania on the color of a base glaze.  I’m now using Pinnell Clear for all of my additive tests as I find it a much better glaze than the traditional Leach 4321.  Further tests could be done using small amounts of manganese, copper and cobalt, as well as varying the fluxes and silica:alumina ratio.  For this test I substituted Grolleg for New Zealand Halloysite, but I did not adjust the recipe to account for the slightly different chemistry.  For this test it is important that the base glaze has as little titania as possible, so it’s best not to use “dirtier” clays.  The test tiles are made from Jingdezhen “super-white” porcelain, which serves as a good blank canvas for the glaze colors.  These glazes look quite different on dirtier porcelains and stoneware.

With the data stored in Glazy it is possible to visualize recipes using graphs and charts.

In the future, these visualizations and more will be added to Glazy at http://glazy.org/graphs

Below are simple pie charts showing the most commonly used glaze materials for both Mid-Fire and High-Fire glazes.

For those who are just starting out with glazes, these charts could be a useful guide when stocking glaze materials.

The charts on the left are for “base” materials, the materials that form the actual glaze.  On the right are charted the “additional” materials- typically colorants and opacifiers- that are added to the base glaze materials.

There are still some strange and untrustworthy recipes in the Glazy database that may have skewed the results somewhat.

Below are the charts for High-Fire glazes.

All of the following ash glaze recipes and more can now be found on my new open-source ceramics recipes website, Glazy:  http://glazy.org/search?category=36&subcategory=96

I’m not particularly an ash glaze aficionado, and I’m far from an expert.  But it’s surprisingly easy to make an interesting ash glaze, and it’s nice to have some “natural” glazes which give interesting surfaces on functional ware.  

The digitalfire website has safety tips for mixing and using ash glazes.

At the bottom of this article is a list of resources for learning more.

A great way to make an ash glaze is to mix any type of ash with your stoneware body.  A line blend of ash from 40-60% is a good place to start.

Below are tests of a local Jiangxi stoneware body, Tianbao, mixed with unwashed ash from my wood stove.  Glazes dipped onto bisqued porcelain and dark stoneware tiles, then fired in reduction to Orton Cone 10.

Below are tests of a local Jiangxi stoneware body, Tianbao, with Rice Straw Ash.

Below are tests of a local Jiangxi stoneware body, Tianbao, with a traditional Jingdezhen glaze ash called Er Hui.

Some ash glazes from The Complete Guide to High Fire Glazes  All tests fired to Orton Cone 10 in reduction.

This recipe, listed in High-Fire Glazes, is simply 50% wood ash and 50% custer feldspar.

As posted by Tom Turner (link below).  He says: “I do not wash ash as I believe much of the character is in what is washed away. Dry sieve through a 30 mesh sieve.”  I used a 60 mesh sieve.

Leach’s Basic Ash Glaze
Wood Ash 40
Feldspar 40
Ball Clay 20

From Phil Rogers Ash Glazes, p. 85:
https://books.google.com/books?id=th3JZzIFFYQC

Also listed on Glazy:  http://glazy.org/recipes/4407

This glaze is from a University of Texas online glaze database (approx 2004) at: http://general.utpb.edu/fac/stanley_c/
http://general.utpb.edu/fac/stanley_c/formulae/glaze/tenmokus.htm

More information on Glazy:  http://glazy.org/recipes/3500

You must burn a lot of wood or plant matter to make a small amount of useable ash.  The sieved, unwashed ash collected after a Winter burning my small wood furnace only gives me enough material to make a couple buckets of 50% clay 50% ash glaze.  Furthermore, I burn whatever type of wood happens my way, and it often contains impurities like dirt and nails.  So besides the limited quantity I have available, there is also a question of consistency.

Substituting part or all of real ash with synthetic ash in a glaze recipe is one method to address the problems of impurities, variability, and supply.

For most of these tests I just made a simple 50/50 mix of the synthetic ash recipe with a local stoneware body in order to compare to my previous real wood ash glazes.  The following tests were all fired to Orton Cone 11 in reduction.

Robert Tichane’s excellent book Ash Glazes has a chapter devoted to synthetic ash glazes.  Based on Dr. Emil Wolff’s analysis of Beech wood ash, Tichane creates the following synthetic ash:

• Limestone: 75 g (43.2%)
• Dolomite: 50 g (30.8%)
• Potassium Carbonate: 25 g (15.4%)
• Bone Ash: 6 g (3.7%)
• Sodium Carbonate: 5 g (3.1%)
• Calcium Sulfate: 3 g (1.9%)
• Silica: 2 g (1.2%)
• Sodium Chloride: 0.2 g (0.1%)
• Ferric Oxide: 1 g (0.6%)

 

As you can see in the third picture, the soluble salts tend to permeate bisque ware, possibly decreasing body melting temperature and increasing warping.  (It would be interesting to compare the effects of solubles on a raw-glazed tile.)  Solubles are troublesome for other reasons, of course.  Water should not be removed from an already mixed glaze batch, and safety is a concern.

 

Tichane’s recipe is interesting because of the soluble components that emulate unwashed wood ash.  And of all the synthetic ash recipes I tested, Tichane’s comes closest to the feel of real unwashed wood ash glazes.

Ash Glazes also contains a recipe for synthetic ash by Maritaro Onishi:

• Limestone: 62%
• Feldspar: 12%
• Bone Ash: 7%
• Magnesite (Magnesium Carbonate): 5%
• Kaolin: 10%
• Silica: 3%

Tichane notes that impurities in the feldspar and kaolin may add iron and manganese.  However, in my test I added an additional 2% red iron oxide and 1.2% manganese dioxide.

John Neely on the Clayart mailing list mentions Etsuzo Katou who published another synthetic ash recipe, Ueda synthetic ash #3:

• Whiting: 59%
• Potash Feldspar: 22%
• Magnesium Carbonate: 11%
• Bone Ash: 5%
• Red Iron Oxide: 2%
• Manganese Dioxide: 1%

I accidentally used 2% Manganese in my test glaze.

In chapter 13 of Chinese Stoneware Glazes, Synthetic Wood Ash, Joseph Grebanier compares various wood ash analyses and questions the accuracy of Onishi’s synthetic ash formula.  Using Herbert Sanders’ ash analyses in The World of Japanese Ceramics,  Grebanier creates the following recipes:

Grebanier’s Batch Recipe for Synthetic “Common Ash”:

• Whiting: 35.73%
• Buckingham Feldspar: 24.35%
• Kaolin: 10.39%
• Flint: 10.11%
• Magnesium Carbonate: 6.86%
• Bone Ash: 4.09%
• Soda Ash: 3.90%
• Red Iron Oxide: 3%
• Manganese Dioxide: 1.32%

Grebanier’s “Common Ash” recipe was later simplified by Phil Rogers in Ash Glazes:

• Whiting: 36%
• Buckingham Feldspar: 25%
• Kaolin: 10%
• Flint: 10%
• Magnesium Carbonate: 7%
• Bone Ash: 5%
• Soda Ash: 4%
• Red Iron Oxide: 3%
• Manganese Dioxide: 1%

Grebanier’s Batch Recipe for Synthetic Pine Ash:

• Whiting: 44.37%
• Orthoclase: 36.17%
• Magnesium Carbonate: 6.36%
• Soda Ash: 4.38%
• Bone Ash: 4.1%
• Red Iron Oxide: 2.31%
• Manganese Dioxide: 2.28%

Grebanier’s Pine Ash recipe was later simplified by Robert Tichane in his Ash Glazes:

• Whiting: 44.4%
• Feldspar: 36.2%
• Magnesium Carbonate: 6.4%
• Soda Ash: 4.4%
• Bone Ash: 4.1%
• Red Iron Oxide: 2.3%
• Manganese Dioxide: 2.3%

In the following tests I substituted Buckingham Feldspar for my local Potash Feldspar.

Many white, clear, and celadon glazes in antiquity were at least in part comprised of plant or tree ash.  By varying the amount of synthetic ash and coloring oxides (mostly iron and manganese) you can quite easily produce some nice glazes.

One of the most important lessons to learn from using synthetic ash is not necessarily to reproduce the look/effect of natural ashes, but rather to understand the result of introducing a wider variety of oxides into the glaze mix.  For instance, take a common celadon recipe, Hamada 5-3-2 (50% custer feldspar, 30% silica, 20% whiting) which is primarily fluxed with lime.  What happens when we introduce extra sodium, potassium, magnesium, phosphorus, iron and manganese to the mix?

One of my favorite ways of making new glazes is to simply mix a flux or ash with a clay body.  This method is usually used with iron-rich stonewares but works just as well for cleaner stoneware and porcelain bodies.

 

For the following three tests, the amount of Iron and Manganese in the synthetic ash was reduced to 1/3 of the original amount.

The first test results in a lovely semi-matte glaze, while the last two tests are passable celadons.

This is basically the Titus-Zella Wood Ash above.

For the potash feldspar/synthetic wood ash mixes above, I reduced the amount of iron and manganese (1/3 of original recipe) as well as added silica to reduce crazing.  With 10% Silica we’ve eliminated the crazing.

Chemical analyses of ash vary widely, even analyses by different people of the same type of ash.  But chemical analyses are a good starting point for experimentation.  Synthetic ash recipes can be calculated by hand (see Chapter 13 of Nigel Wood’s Chinese Glazes) or by using glaze software.

I was interested in Issu wood ash, commonly used in Japan for making celadon glazes.  The chemical analyses for Issu wood  (see list by Linda Arbuckle below) are:

	SiO2	Al2O3	TiO2	Fe2O3	CaO	MgO	K2O	Na2O	MnO	P2O5
Herbert Sanders, The World of Japanese Ceramics	34.6	4.38		0.49	47.71	5.99	2.51	0.06	0.33	3.93
Cardew	16.19	4.16		0.92	36.68	6.6	1	0.2	0.48	0.92
J.B.E. Patterson (via Leach, A Potter’s Book)	71.96	0.63		0.28	15.95	1.57	0.84			0.42

As you can see, there’s a huge difference between these three analyses, it’s difficult to know if any of them are to be trusted.  So I checked Grebanier’s Chinese Stoneware Glazes and was surprised to find that he had come across the exact same problem (Chapter 13, Synthetic Wood Ash).  Grebanier seems to have abandoned hope of finding an Issu ash substitute, but I went ahead with Sanders’ analysis as it seemed more trustworthy.

(Actually, perhaps it’s not that Sanders’ analysis is more trustworthy as much as the fact that it’s more interesting to me.)

I calculated two recipes, one using only Whiting and one minimizing the amount of Whiting by using Wollastonite (without adding too much Silica) and replacing Magnesium Carbonate with Dolomite (in order to provide MgO as well as CaO).

Recipe 1 (Whiting):

• Whiting 53.36
• Custer Feldspar 13.97
• Silica 13.76
• Magnesium Carb 9.72
• Bone Ash 6.63
• New Zealand Kaolin 2.03
• Iron 0.31
• Manganese Dioxide 0.23
• Total: 100.01

Recipe 2 (Minimize Whiting):

• Whiting 21.35
• Wollastonite 29.86
• Dolomite 23.14
• Custer Feldspar 15.46
• Bone Ash 7.34
• New Zealand Kaolin 2.25
• Iron 0.35
• Manganese Dioxide 0.26
• Total: 100.01

Ash Glazes by Robert Tichane.

The Complete Guide to High Fire Glazes by John Britt.  Besides being my favorite introduction book on glazes, there is a section on ash and synthetic ash glazes.

Chinese Stoneware Glazes by Joseph Grebanier.  Joseph uses ash in many of his glazes in order to re-create ancient Chinese glazes.

Ash Glazes by Phil Rogers.  I have not yet read this book, but the reviews are good and the book preview on Google Books looks promising.

Ash Glaze on the Digitalfire.com website.  Also information on wood ash, hardwood ash, softwood ash, rice straw ash,  and rice husk ash.

Nigel Wood’s Chinese Ceramics and Science and Civilisation in China: Volume 5, Chemistry and Chemical Technology, Part 12, Ceramic Technology both contain a wealth of information of the role of wood and plant ash in the development of Chinese glazes, including chemical analyses of ashes and comparisons with glaze compositions.

Some ash glaze recipes can be found on Rick’s Bricks and Tom Turner’s website.

The following information is from a Linda Arbuckle handout, GlazeChem Materials.

Bamboo ash

% 4.8 K2O 0.3 CaO 86.4 SiO2 0.4 Fe2O3 8.1 LOI

Bamboo ash supplies several oxides, especially SiO2.

Analyses:

Cardew:

% 4.8 K2O 0.3 CaO 86.4 SiO2 0.4 Fe2O3 8.1 LOI

(‘Bamboo sugar’, Java) (Bourry, 1st English edition, 1901)

Barley straw ash

% 5 Na2O 22 K2O 3 MgO 8 CaO 57 SiO2 5 P2O5

Barley straw ash supplies several oxides, especially SiO2 and K2O.

Analyses:

Hamer & Hamer:

% 5 Na2O 22 K2O 3 MgO 8 CaO 57 SiO2 5 P2O5

Beech ash

% 8.34 Na2O 24.29 K2O 8.20 MgO 42.00 CaO 3.01 SiO2 6.2 P2O5 0.62 Fe2O3 4.52 MnO 2.10 SO3 0.72 Cl

Beech ash supplies several oxides, especially CaO and K2O.

Analyses:

Rogers:

% 8.34 Na2O 24.29 K2O 8.20 MgO 42.00 CaO 3.01 SiO2 6.2 P2O5 0.62 Fe2O3 4.52 MnO 2.10 SO3 0.72 Cl

Rogers (appendix):

% 4.0 Na2O 16.5 K2O 10.9 MgO 55.5 CaO 5.45 SiO2 5.45 P2O5 1.0 Fe2O3

Birch ash

% 9 Na2O 22.6 K2O 14.3 MgO 29.6 CaO 11.5 SiO2 7.9 P2O5 1.3 Fe2O3 0.4 MnO 3.4 LOI

Birch ash supplies several oxides, especially CaO and K2O.

Analyses:

Conrad:

% 9 Na2O 22.6 K2O 14.3 MgO 29.6 CaO 11.5 SiO2 7.9 P2O5 1.3 Fe2O3 0.4 MnO

Rogers (appendix):

% 7.69 Na2O 12.53 K2O 7.69 MgO 57.5 CaO 3.84 SiO2 7.69 P2O5 1.0 Fe2O3

Hamer & Hamer:

% 9 Na2O 18 K2O 11 MgO 45 CaO 4 Al2O3 8 SiO2 4 P2O5 1 Fe2O3

Cedar ash

% 3.7 Na2O 4.3 K2O 6 MgO 44.2 CaO 0.52 Al2O3 24.28 SiO2 10.6 P2O5 1.01 Fe2O3 0.3 MnO 5.09 LOI

Cedar ash supplies several oxides, especially CaO and SiO2.

Analyses:

Conrad:

% 3.7 Na2O 4.3 K2O 6 MgO 44.2 CaO 0.52 Al2O3 24.28 SiO2 10.6 P2O5 1.01 Fe2O3 0.3 MnO

Common ash

% 2.33 Na2O 3.91 K2O 3.3 MgO 22.42 CaO 8.91 Al2O3 30.99 SiO2 1.91 P2O5 3.04 Fe2O3 1.26 MnO 21.44 LOI

Common ash supplies several oxides, especially SiO2 and CaO.

Analyses:

Sanders:

% 2.33 Na2O 3.91 K2O 3.3 MgO 22.42 CaO 8.91 Al2O3 30.99 SiO2 1.91 P2O5 3.04 Fe2O3 1.26 MnO 21.44 LOI

Desert plant ash

% 28.0 Na2O 5.5 K2O 0.5 MgO 21.1 CaO 1.8 P2O5 34.0 CO2

Desert plant ash supplies several oxides, especially Na2O and CaO.

Analyses:

Tichane (TCB): (adds to 91%)

% 28.0 Na2O 5.5 K2O 0.5 MgO 21.1 CaO 1.8 P2O5 34.0 CO2

Elder ash

% 2 Na2O 17 K2O 16 MgO 38 CaO 14 SiO2 13 P2O5

Elder ash supplies several oxides, especially CaO.

Analyses:

Hamer & Hamer:

% 2 Na2O 17 K2O 16 MgO 38 CaO 14 SiO2 13 P2O5

Fern ash

% 0.56 Na2O 4.81 K2O 7.44 MgO 8.59 CaO 19.32 Al2O3 55.02 SiO2 0.3 TiO2 0.92 P2O5 1.67 Fe2O3 1.36 MnO

Fern ash supplies several oxides, especially SiO2 and Al2O3.

Analyses:

Rogers (appendix):

% 0.56 Na2O 4.81 K2O 7.44 MgO 8.59 CaO 19.32 Al2O3 55.02 SiO2 0.3 TiO2 0.92 P2O5 1.67 Fe2O3 1.36 MnO

Hamer & Hamer: (Bracken and fern)

% 3 Na2O 26 K2O 8 MgO 12 CaO 10 Al2O3 33 SiO2 6 P2O5 1 Fe2O3 1 MnO

Grass ash

0.2 KNaO 0.3 MgO 0.5 CaO 0.2 Al2O3 2.0 SiO2

Grass ash supplies several oxides, especially SiO2 and CaO.

Generic grass ash.

Green: (weed and grass ash)

0.2 KNaO 0.3 MgO 0.5 CaO 0.2 Al2O3 2.0 SiO2

Green: (unwashed lawn clippings, from Leach “A Potter’s Book”)

0.41 KNaO 0.29 MgO 0.30 CaO 0.27 Al2O3 1.09 SiO2 0.12 P2O5 0.03 Fe2O3

Green: (washed lawn clippings, from Leach “A Potter’s Book”)

0.15 KNaO 0.32 MgO 0.53 CaO 0.38 Al2O3 1.52 SiO2 0.15 P2O5 0.05 Fe2O3

Rogers: (Lawn grass)

% 6.20 Na2O 6.19 K2O 5.65 MgO 12.88 CaO 16.60 Al2O3 39.64 SiO2 9.00 P2O5 3.44 Fe2O3

Hamer & Hamer: (Lawn grass)

% 3 Na2O 5 K2O 5 MgO 10 CaO 11 Al2O3 59 SiO2 5 P2O5 2 Fe2O3

Mixed hardwood ash

% 9.12 Na2O 14 K2O 12 MgO 30 CaO 0.1 Al2O3 15.3 SiO2 13.1 P2O5 2.4 Fe2O3 0.1 MnO 3.88 LOI

Hearth ash

% 0.55 Na2O 1.49 K2O 5.44 MgO 35.9 CaO 3.69 Al2O3 14.08 SiO2 2.14 P2O5 0.94 Fe2O3 34.32 h3O 0.14 MnO

Hearth ash supplies several oxides, especially CaO and SiO2.

Analyses:

Cardew:

% 0.55 Na2O 1.49 K2O 5.44 MgO 35.9 CaO 3.69 Al2O3 14.08 SiO2 2.14 P2O5 0.94 Fe2O3 34.32 h3O 0.14 MnO

(Hearth ash (‘Dobai’), Japan (E. Kato, Interceram, 2 (1962), 110).)

Heather ash

% 9 Na2O 12 K2O 10 MgO 21 CaO 41 SiO2 5 P2O5 2 Fe2O3

Heather ash supplies several oxides, especially SiO2 and CaO.

Analyses:

Hamer & Hamer:

% 9 Na2O 12 K2O 10 MgO 21 CaO 41 SiO2 5 P2O5 2 Fe2O3

Issu-wood ash

% 0.06 Na2O 2.51 K2O 5.99 MgO 47.71 CaO 4.38 Al2O3 34.6 SiO2 3.93 P2O5 0.49 Fe2O3 0.33 MnO

Isu-wood ash supplies several oxides, especially CaO and SiO2.  Issu (Distylium racemosum) is the source of a very popular wood ash in Japan. Note the incredible variations in the analyses.

Analyses:

Sanders:

% 0.06 Na2O 2.51 K2O 5.99 MgO 47.71 CaO 4.38 Al2O3 34.6 SiO2 3.93 P2O5 0.49 Fe2O3 0.33 MnO

Cardew:

% 0.2 Na2O 1 K2O 6.6 MgO 36.68 CaO 4.16 Al2O3 16.19 SiO2 3.67 P2O5 0.92 Fe2O3 30.08 h3O 0.8 SO3 0.48 MnO

(Isu Ash from Hagi, Japan (E. Kato, Interceram, 2 (1962), 110).)

Leach (“A Potter’s Book”):

% 0.84 K2O 1.57 MgO 15.95 CaO 0.63 Al2O3 71.96 SiO2 0.42 P2O5 0.28 Fe2O3 8.29 LOI

(from work done by J.B.E. Patterson)

Ivy ash

% 20 Na2O 26 K2O 8 MgO 25 CaO 12 SiO2 6 P2O5 3 Fe2O3

Ivy ash supplies several oxides, especially CaO, K2O, and Na2O.

Analyses:

Hamer & Hamer:

% 20 Na2O 26 K2O 8 MgO 25 CaO 12 SiO2 6 P2O5 3 Fe2O3

Larch wood ash

% 9 Na2O 21 K2O 8 MgO 27 CaO 1 Al2O3 11 SiO2 8 P2O5 4 Fe2O3 11 MnO

Larch wood ash supplies several oxides, especially CaO, K2O, SiO2, and MnO.

Analyses:

Hamer & Hamer:

% 9 Na2O 21 K2O 8 MgO 27 CaO 1 Al2O3 11 SiO2 8 P2O5 4 Fe2O3 11 MnO

Mahogany ash

% 10.98 Na2O 9.49 K2O 4.39 MgO 9.49 CaO 3.81 Al2O3 51.51 SiO2 2.08 P2O5 4.53 Fe2O3 3.72 LOI

Mahogany ash supplies several oxides, especially SiO2.

Analyses:

Cardew:

% 10.98 Na2O 9.49 K2O 4.39 MgO 9.49 CaO 3.81 Al2O3 51.51 SiO2 2.08 P2O5 4.53 Fe2O3

(Australian white mahogany) (Forestry Commission of New South Wales, 1956)

Maple ash

% 6.04 Na2O 6.2 K2O 12.05 MgO 27.5 CaO 0.9 Al2O3 13.8 SiO2 8.1 P2O5 2.5 Fe2O3 0.5 MnO 22.41 LOI

Maple ash supplies several oxides, especially CaO.

Analyses:

Conrad:

% 6.04 Na2O 6.2 K2O 12.05 MgO 27.5 CaO 0.9 Al2O3 13.8 SiO2 8.1 P2O5 2.5 Fe2O3 0.5 MnO

Meadow hay ash

% 7.0 Na2O 25.67 K2O 5.0 MgO 11.56 CaO 29.57 SiO2 6.2 P2O5 1.0 Fe2O3

Meadow hay ash supplies several oxides, especially SiO2 and K2O.

Analyses:

Rogers (appendix):

% 7.0 Na2O 25.67 K2O 5.0 MgO 11.56 CaO 29.57 SiO2 6.2 P2O5 1.0 Fe2O3

Hamer & Hamer: (Meadow grass)

% 4 Na2O 15 K2O 5 MgO 10 CaO 3 Al2O3 58 SiO2 4 P2O5 1 Fe2O3

Mixed wood ash

0.125 Na2O 0.266 K2O 0.187 MgO 0.422 CaO 0.016 Al2O3 0.375 SiO2 0.109 P2O5 0.062 Fe2O3

 

Oak ash

% 9.12 Na2O 14 K2O 12 MgO 30 CaO 0.1 Al2O3 15.3 SiO2 13.1 P2O5 2.4 Fe2O3 0.1 MnO 3.88 LOI

Oak ash supplies several oxides, especially CaO.

Analyses:

Conrad:

% 9.12 Na2O 14 K2O 12 MgO 30 CaO 0.1 Al2O3 15.3 SiO2 13.1 P2O5 2.4 Fe2O3 0.1 MnO

Tichane (TCB):

% 3.9 Na2O 9.5 K2O 3.9 MgO 72.5 CaO 2.0 SiO2 5.8 P2O5

Rogers: (English oak)

% 9.12 Na2O 14.00 K2O 12.01 MgO 30.02 CaO 0.13 Al2O3 15.30 SiO2 13.8 P2O5 2.40 Fe2O3 0.10 MnO 0.05 CuO 2.61 SO3 1.18 Cl

Rogers (appendix): (China)

% 1.47 Na2O 5.77 K2O 4.09 MgO 23.54 CaO 15.11 Al2O3 39.81 SiO2 2.3 P2O5 3.58 Fe2O3 4.32 MnO

Rogers (appendix): (Japan)

% 1.52 Na2O 5.68 K2O 4.14 MgO 23.69 CaO 16.34 Al2O3 39.62 SiO2 2.62 P2O5 3.83 Fe2O3 1.01 MnO

Hamer & Hamer:

% 6 Na2O 11 K2O 9 MgO 51 CaO 1 Al2O3 10 SiO2 10 P2O5 1 Fe2O3 1 MnO

Straw ash

0.4 KNaO 0.2 MgO 0.4 CaO 2.7 SiO2 0.1 P2O5

Straw ash supplies several oxides, especially SiO2.  Generic straw ash.

Analyses:

Green: (straw ash from cereal crops)

0.4 KNaO 0.2 MgO 0.4 CaO 2.7 SiO2 0.1 P2O5

Tallowwood ash

% 6.84 Na2O 2.41 K2O 25.58 MgO 52.15 CaO 1.09 Al2O3 8.96 SiO2 0.4 P2O5 1.93 SO3 0.38 Cl2 0.18 MnO

Tallowwood ash supplies several oxides, especially CaO and MgO.

Analyses:

Cardew:

% 6.84 Na2O 2.41 K2O 25.58 MgO 52.15 CaO 1.09 Al2O3 8.96 SiO2 0.4 P2O5 1.93 SO3 0.38 Cl2 0.18 MnO

(Eucalyptus microscorys III (Tallowwood) Forestry Commission of New South Wales, 1956)

Thatching grass ash

% 0.22 Na2O 2.55 K2O 3.67 MgO 6.14 CaO 5.42 Al2O3 76.96 SiO2 1.58 P2O5 0.22 TiO2 1.06 Fe2O3 0.15 SO3 0.67 MnO 1.4 LOI

Thatching grass ash supplies several oxides, especially SiO2.

Analyses:

Cardew:

% 0.22 Na2O 2.55 K2O 3.67 MgO 6.14 CaO 5.42 Al2O3 76.96 SiO2 1.58 P2O5 0.22 TiO2 1.06 Fe2O3 0.15 SO3 0.67 MnO 1.4 LOI

(Abuja, Nigeria. Wahsed and calcined at 900C) (Overseas Geological Surveys, London, 1966)

Turpentine ash

% 4.08 Na2O 1.2 K2O 1.03 MgO 1.88 CaO 1.26 Al2O3 89.74 SiO2 0.39 P2O5 0.42 LOI

Turpentine ash supplies several oxides, especially SiO2.

Analyses:

Cardew:

% 4.08 Na2O 1.2 K2O 1.03 MgO 1.88 CaO 1.26 Al2O3 89.74 SiO2 0.39 P2O5

(Australian turpentine) (Forestry Commission of New South Wales, 1956)

Wheat straw ash

% 2.8 Na2O 11.5 K2O 2.5 MgO 6.1 CaO 66.2 SiO2 5.4 P2O5 2.8 SO3 3.8 S

Wheat straw ash supplies several oxides, especially SiO2 and K2O.

Analyses:

Cardew:

% 2.8 Na2O 11.5 K2O 2.5 MgO 6.1 CaO 66.2 SiO2 5.4 P2O5 2.8 SO3 3.8 S

(Air dried) (B.C.S., (1959), 59P)

Green:

0.67 K2O 0.14 MgO 0.19 CaO 0.71 Al2O3 4.95 SiO2 0.10 P2O5

Tichane (TCB):

% 2.8 Na2O 11.5 K2O 2.5 MgO 6.1 CaO 66.0 SiO2 5.4 P2O5 2.8 LOI

Rogers:

% 1.4 Na2O 13.6 K2O 2.5 MgO 5.8 CaO 67.5 SiO2 4.8 P2O5 0.6 Fe2O3

Hamer & Hamer:

% 2 Na2O 13 K2O 4 MgO 6 CaO 70 SiO2 5 P2O5

Willow ash

% 2.50 Na2O 49.80 K2O 8.26 MgO 20.21 CaO 0.05 Al2O3 4.44 SiO2 10.00 P2O5 1.25 Fe2O3 0.18 MnO 1.22 SO3 0.08 Cl

Willow ash supplies several oxides, especially K2O, CaO, and P2O5.

Analyses:

Rogers:

% 2.50 Na2O 49.80 K2O 8.26 MgO 20.21 CaO 0.05 Al2O3 4.44 SiO2 10.00 P2O5 1.25 Fe2O3 0.18 MnO

1.22 SO3 0.08 Cl

Hamer & Hamer:

% 3 Na2O 51 K2O 9 MgO 21 CaO 5 SiO2 10 P2O5 1 Fe2O3

Ash wood ash

0.125 Na2O 0.266 K2O 0.187 MgO 0.422 CaO 0.016 Al2O3 0.375 SiO2 0.109 P2O5 0.062 Fe2O3

Ash wood ash supplies several oxides, especially CaO and SiO2.

Analyses:

Hamer & Hamer:

% 8 Na2O 17 K2O 12 MgO 27 CaO 1 Al2O3 24 SiO2 7 P2O5 4 Fe2O3