Ceramic Glaze Theory and Practice

1. Ceramic Glazes: Theory and
Practice
Bryant Hudson
May 21, 2009

2. Goals
• Better understand how glazes work
• Become familiar with glaze compositions
• Become familiar with glaze ingredients
• Learn how to mix glazes
• Learn how to compare glazes
• Understand oxidation and reduction firing
• Look at the Firehouse Studio glazes in detail

3. What is a Glaze ?
• Glass that sticks to pottery
• Glazes are mostly Silica
• Pure Silica melts at 3100F
• Add Sodium and Calcium to
lower melting point (fluxes)
• Add Aluminum to increase
the viscosity

4. Periodic Table of the Elements
Lots of elements to consider
We want to work with common inexpensive materials
Low hazard and non-volatile

5. Elements we use in the
current set of studio glazes
Of course everything is combined with Oxygen

6. Alkali Metals
Strong fluxes active at all temperatures
Lithium Carbonate (toxic)
Na Feldspar – F4 feldspar
Nepheline syenite
Sodium Carbonate – Soda Ash (soluble, toxic)
Potassium Feldspar – Custer Feldspar

7. Alkaline Earth Metals and Zinc
Strong fluxes active at higher temperature
Magnesium Calcium Carbonate – Dolomite
Magnesium Silicate – Talc
Magnesium Carbonate
Calcium Carbonate – Whiting
Strontium Carbonate
Strontium Oxide
Zinc Oxide

8. Non-metals and Aluminum
These elements go into the basic glass network
Gerstley Borate
Borax
Clays
Feldspars
Silicon dioxide – Quartz, Flint
Clays
Feldspars
Calcium Phosphate – Bone Ash

9. Transition Metals - COLOR
Chromium Oxide (toxic)
Iron Chromate (toxic)
Iron Oxide (Fe2O3 – red, Fe3O4 –black)
Copper Carbonate (toxic)
Cobalt Carbonate (toxic)

10. Opacifiers to decrease glaze
transparency
Titanium Dioxide – Rutile (>85% TiO2)
Zirconium Silicate – Zircopax, Ultrox
Tin Oxide

11. 17 Glazes from 18 Oxides derived from
27 different materials
Al2O3 Bentonite
3D BLACK Black Iron Oxide
TOMATO RED B2O3 Bone Ash
CaO Borax
BOB'S BLUE MATT Chrome Oxide
CoO Cobalt Carbonate
BRINGLE'S GREEN Copper Carbonate
Cr2O3
BUTTERMILK Custer Feldspar
CuO Dolomite
DEPENDABLE RED FeO EPK Kaolin
F-4 Feldspar
GAIL'S WHITE K2O Ferro 3134
LAURA'S TURQUOISE Li2O Gerstley Borate
Lithium Carbonate
MYSTERY BLUE MgO Magnesium Carbonate
Na2O Nepheline Syenite
PIER BLACK OM-4 Ball Clay
RACHEL'S BLUE P2O5 Red Iron Oxide
SiO2 Rutile
RUTILE Silica
SnO2 Strontium Carbonate
SEAFOAM Talc
SrO
SPECKLED LAVENDER Tenn #10 Ball Clay
TiO2 Tin Oxide
TENMOKU ZnO Ultrox (Zircopax)
Whiting
WOO BROWN TO BLUE ZrO2 Zinc Oxide
YELLOW SALT

12. Clays Bentonite
EPK (Kaolin)
Primary source of OM-4 Ball Clay
Aluminum Tennessee #10 Ball Clay
Feldspars Custer Feldspar
F-4 Feldspar
Primary source of Li, Nepheline Syenite
Na, and K, and also Spodumene
provide Silica and
Aluminum

13. Soda Ash
Fluxes Lithium Carbonate
Strontium Carbonate
Strontium Oxide
Sources of Lithium, Magnesium Carbonate
Sodium, Magnesium, Dolomite
Calcium and Strontium Talc
Whiting

14. Borax
Glass makers Ferro 3134
Sources of Boron, Gerstley Borate
Silica and Silica
Phosphorus Bone Ash
Rutile
Opacifiers Tin Oxide
Sources of Titanium, Zinc Oxide
Tin, Zinc and Zirconium Ultrox (Zircopax)

15. Chrome Oxide
Colorants Cobalt Carbonate
Copper Carbonate
Red Iron Oxide
Black Iron Oxide

16. Carbonates vs. Oxides or Silicates
• Carbonates • Oxides or Silicates
– Easier to make fine – Can be coarse and heavy
powders and hard to disperse
– Lower density and easier – No gas production
to suspend in glaze – Less toxic because they
– Produce large amounts are harder to absorb
of CO2 – bubbles – Higher density means
– Generally more toxic less material required
Cobalt Carbonate vs. Cobalt Oxide
Calcium Carbonate (whiting) vs. Wollastonite (CaSiO4)

17. Some of these compounds are toxic
Lithium , Copper, Cobalt and Chromium
are elements of concern
Eat a spoonful of these and you will get sick or die
We need small amounts in our diet to be healthy
(1mg/d Li, 2mg/d Cu, 0.1 mg/d Co, 10mg/d Cr)

18. Chronic inhalation of dust
• Regular inhalation of fine silica dust causes long term
health problems
• Fine silica powder is a mainstay of both clays and
glazes
• This is the number one health
concern in the studio

19. Keep Dust Levels Low !
• Clean up drips and spills
• Don’t dry sweep
• Don’t dry sand inside the studio
• If you have an apron, wash it regularly
• If you have a towel, keep it damp, wash it
• Transfer large bags of powder outside
• …

20. Material Properties
CAS # density solubility LD50 dust health
g/cm3 g/L H2O mg/kg (rat) hazard NFPA
Bentonite 1302-78-9 2.5 0 na serious 2
Black Iron Oxide 1317-61-9 5.2 0 20000 nuisance 0
Bone Ash 1306-06-5 3.1 0 10000 nuisance 0
Borax 1330-43-4 2.4 25 2400 moderate 1
Chrome Oxide 1308-38-9 5.2 0 10000 serious 2
Cobalt Carbonate 12602-23-2 4.1 0 640 serious 2
Copper Carbonate 12069-69-1 4.0 0 1350 nuisance 1
Custer Feldspar 68476-25-5 2.6 0 na serious 1
Dolomite 16389-88-1 2.8 0 6450 nuisance 1
EPK Kaolin 1332-58-7 2.7 0 na serious 2
F-4 Feldspar 68476-25-5 2.6 0 na serious 1
Ferro Frit 3134 65997-18-4 2.0 0 na moderate 1
Gerstley Borate 12046-09-2 2.4 5 >5000 nuisance 0
Lithium Carbonate 554-13-2 2.1 13 525 serious 2
Magnesium Carbonate 546-93-0 3.0 0 na nuisance 1

21. CAS # density solubility LD50 dust health
g/cm3 g/L H2O mg/kg (rat) hazard NFPA
Nepheline Syenite 37244-96-5 2.6 0 na nuisance 0
OM-4 Ball Clay 1332-58-7 2.5 0 na serious 2
Red Iron Oxide 1309-37-1 5.2 0 20000 nuisance 1
Rutile 1317-80-2 4.1 0 na nuisance 0
Silica 14808-60-7 2.7 0 na serious 2
Soda Ash (sodium carbonate) 497-19-8 2.5 300 4090 moderate 2
Strontium Carbonate 1633-05-2 3.5 0 >2000 nuisance 1
Talc 14807-96-6 2.6 0 na moderate 1
Tenn #10 Ball Clay 1332-58-7 2.5 0 na serious 2
Tin Oxide 1332-29-2 7.0 0 20000 serious 2
Ultrox (Zircopax) 14940-68-2 4.7 0 na serious 1
Whiting (calcium carbonate) 471-34-1 2.8 0 6450 nuisance 1
Wollastine 13983-17-0 2.8 0 na nuisance 0
Zinc Oxide 1314-13-2 5.6 0 na nuisance 0
CAS # - universal database number
LD50 (rat) – 50% of rats will die if the consume this much material
NFPA Health – 0 nontoxic, 1 slightly toxic, 2 moderately toxic, 3 highly toxic, 4 extremely toxic

22. Useful Information
• http://digitalfire.com/4sight/material/

23. Melting Mixtures
• Many of the glaze
compounds melt at very
high temperatures
• Mixtures of these
compounds melt at
lower temperatures
(Eutectic = easy to melt)

24. A simple real-world phase diagram

25. The first objects in the solar
system were ceramic
The small white
inclusions are
Ca-Al-silicates
We can study their compositions and compare to known phase
diagrams to infer the conditions under which they formed

26. On an atomic scale our ingredients
are big
• Melting begins at the
contact points
• Our “small” particles are
still tens of thousands of
atoms wide
• This affects how the
glaze melts

27. Kilns
Electric Gas or Wood
• Oxygen atmosphere • Combustion gas atmosphere
• Precise temperature • Moderate temperature
control control
• Generally below 2250F • Routine operation to 2350F
(cone 6) to increase
filament life but can go to (cone 10)
cone 10 • Capable of producing
reduction atmosphere
• Reduction difficult • Difficult to control

28. Combustion
• CH4 + 2O2 CO2 + 2H2O (890 J/mole)
– All the oxygen is consumed
– Maximum heat production
• CH4 + O2 CO + H2 + H2O (36 J/mole)
– Not enough oxygen for complete combustion
– Most of the fuel energy escapes
– Large amount of carbon monoxide produced

29. There are many possibilities
• CH4 +yO2 aCO2 + bCO +cH2 + dH2O + eC
• Even molecules like CH3OH (methanol)
• Details matter - burner geometry, kiln size
• Gas kilns differ greatly

30. Why care about reduction ?
• CO + 2CuO Cu2O + CO2
• Color changes in the
transition metal colorants

31. Timing in the firing matters
• Before the glaze melts, the glaze and clay are
porous and interact with the kiln atmosphere
• Once the glaze melts, the interaction with the
kiln atmosphere takes place by diffusion –
much slower

32. Timing in cooling matters
• Once the burners are off, the atmosphere
suddenly changes to being oxygen rich
• As the glaze cools, some liquids or solids by
come out of solution
• Crystal formation is critical to copper red
glazes
• Crystal formation and phase separation give
rise to many of the effects we like

33. Safety in firing the gas kiln
• Carbon Monoxide – very toxic
• You can hurt your eyes looking in the kiln
• Volatile compounds
– organic, sulfurous, metallic compounds
Gases coming from the kiln, especially during reduction
are dangerous. Stay away from the kiln during firing.
Beware of the possibility of kiln exhaust entering the
studio

34. Evaluating Glaze Compositions
• Lots of different ingredients bring in some of
the same oxides and it can be hard to
compare glaze recipes
• We need to be able to transform glaze recipes
into lists of basic oxides
• Instead of using weights, it is useful to
calculate relative number of molecules

35. Calculating Molecular Fractions
• Need to know the composition of each ingredient and what
disappears during firing
Custer Feldspar OM #4 Ball Clay Calcium Carbonate
(whiting)
CaO 0.30 CaO 0.30
K2O 10.28 K2O 1.00 CaO 56.10
Na2O 2.91 MgO 0.40
Al2O3 17.35 Na2O 0.30 LOI 43.90
SiO2 69.00 TiO2 1.20
Fe2O3 0.12 Al2O3 27.90
SiO2 55.20
LOI 0.04 Fe2O3 1.10
LOI 12.60
Values are weight % LOI = Loss On Ignition

36. Add pieces and normalize
A recipe for a simple clear glaze
70% 10% 20%
Oxide Mole wt. Custer F. OM4 BC Whiting weight moles mole %
CaO 56.1 0.3 0.3 56.1 11.5 0.2043 14.8%
K2O 94.2 10.3 1.0 7.3 0.0775 5.6%
MgO 40.3 2.9 0.4 2.1 0.0515 3.7%
Na2O 62.0 0.3 0.0 0.0005 0.0%
TiO2 80.1 1.2 0.1 0.0015 0.1%
Al2O3 101.9 17.4 27.9 14.9 0.1466 10.6%
SiO2 60.0 69.0 55.2 53.8 0.8970 65.0%
Fe2O3 159.7 0.1 1.1 0.2 0.0012 0.1%

37. Seger Unity Formula
Seger Formula: Normalize the mole % values to the sum of the fluxes
Oxide Mole % Seger Oxide Mole % Seger
CaO 0.1480 0.61 SiO2 0.6500 2.678
K2O 0.0561 0.23 Al2O3 0.1062 0.438
MgO 0.0373 0.15 TiO2 0.0011 0.004
Na2O 0.0004 0.00
Fe2O3 0.0009 0.00
sum 0.2427
The Seger formula for a cone 6 cone has SiO2 = 6,
a cone 7 cone has SiO2 = 7…

38. Mixing Glazes
• Read and understand the recipe
• Check to see if you have the ingredients
• Equipment:
– A scale to weigh materials
– Containers to weigh materials and mix materials
– Sieves to do the final mixing
– Graduated cylinder and funnel to measure specific
gravity
– Protective equipment, dusk mask, gloves …

39. What I do to mix a glaze
1) Start with 0.5 liter of water per 1000g of dry material
2) Start with the hard to mix materials first
1) Bentonite, ball clay, EPK
3) Mix each ingredient as you add it
4) Add water to bring the specific gravity close to the
correct value so the glaze isn’t too thick but still needs a
little more water
5) Take notes (and keep them) of what you did
6) Take a break (30 min – a day) for material to hydrate – it
will be easier to sieve and mix

40. What I do to mix a glaze
7) Spend several minutes with the drill mixer to thoroughly
mix the glaze
8) Sieve the glaze a couple time (80 mesh, check recipe)
9) Check the specific gravity and add water to bring it to
the correct value (about 1.6 – check recipe)
10) Check the thickness (viscosity). Test how it coats a
piece of bisque pottery (want about 1mm)
11) If the glaze is thin, add epsom salt (MgSO4)
(20g/10000g glaze) at a time until the glaze is thickened
– no more than 100g/10000g total
12) Clean up the mess

41. Measuring Specific Gravity
• Specific gravity is the measured density
divided by the density of water
• Weigh 100 ml of glaze and divide the weight
by 100
• Measuring specific gravity is the best way to
know how much water to add

44. Glaze Flocculation
• Glazes are complex liquids – a suspension of fine particles
• Clay particles have interesting surface properties and
depending on what’s dissolved in the glaze, they will stick
together
• Dissolved Ca and Mg will cause glazes containing clay to
flocculated
• A flocculated glaze works well for dipping application
• If a glaze doesn’t contain much clay, bentonite can be
added (1-2%)
• Some glazes will de-flocculate over time due to materials
going into solution. Add small amounts of epsom salt
(MgSO4) to re-flocculate the glaze

45. Glaze Flocculation
• http://www.claytimes.com/articles/glazeadjusting.html
• Adjusting Glazes for Application by Pete
Pinnell, From the March/April and May/June
1998 issues of Clay Times

46. Measuring Glaze Thickness
• Applying glaze at the proper thickness is
important
• Know the glaze and measure the thickness
Use a razor blade to scrape a 90 degree
scratch in the glaze. The width at the
top is twice the thickness of the glaze

47. Summary of Glazes
SiO2 Al2O3 B2O3 P2O3 TiO2 SnO2 ZrO2 Li2O K2O Na2O CaO MgO SrO ZnO Cr2O3 CoO CuO FeO
3D BLACK 0.75 0.07 0.01 0.03 0.08 0.004 0.05
TOMATO RED 0.65 0.08 0.02 0.02 0.03 0.08 0.05 0.06
BOB'S BLUE MATT 0.60 0.12 0.02 0.07 0.01 0.17 0.013
BRINGLE'S GREEN 0.51 0.09 0.01 0.04 0.02 0.06 0.13 0.10 0.033 0.01
BUTTERMILK 0.65 0.05 0.03 0.03 0.02 0.01 0.11 0.09
DEPENDABLE RED 0.65 0.07 0.02 0.005 0.02 0.04 0.12 0.02 0.04 0.004
GAIL'S WHITE 0.67 0.12 0.02 0.04 0.02 0.04 0.08
LAURA'S TURQUOISE 0.51 0.11 0.03 0.02 0.01 0.30 0.002 0.020
MYSTERY BLUE 0.71 0.07 0.03 0.03 0.01 0.14 0.006
PIER BLACK 0.50 0.12 0.01 0.04 0.02 0.14 0.08 0.02 0.042 0.03
RACHEL'S BLUE 0.69 0.07 0.04 0.03 0.03 0.13 0.007
RUTILE 0.63 0.08 0.07 0.02 0.01 0.14 0.05
SEAFOAM 0.70 0.07 0.03 0.03 0.01 0.14 0.022
SPECKLED LAVENDER 0.67 0.06 0.02 0.005 0.02 0.04 0.03 0.12 0.01 0.03 0.003 0.003
TENMOKU 0.68 0.07 0.03 0.01 0.12 0.08
WOO BROWN TO BLUE 0.70 0.07 0.03 0.03 0.01 0.12 0.03
YELLOW SALT 0.54 0.11 0.06 0.02 0.07 0.09 0.07 0.04
Values are mole %

48. Seger Mol%
3D Black
3D BLACK FH KNO
CaO
0.239
0.457
4.42%
8.44%
Silica 37.0 Al2O3 0.372 6.87%
F-4 Feldspar 44.0 SiO2 4.043 74.65%
Whiting 12.0 TiO2 0.001 0.02%
EPK Kaolin 7.0 K2O 0.062 1.14%
Na2O 0.178 3.28%
Red Iron Oxide 6.4
CoO 0.034 0.43%
Cobalt Carbonate 0.8
FeO 0.280 5.18%

50. Seger Mol%
Tomato Red
TOMATO RED FH KNO
CaO
0.206
0.325
5.19%
8.21%
MgO 0.215 5.43%
F-4 Feldspar 48.22 Al2O3 0.311 7.85%
Silica 25.89 P2O5 0.092 2.31%
SiO2 2.56 64.59%
EPK Kaolin 7.14 TiO2 0.001 0.02%
Magnesium Carbonate 7.14 K2O 0.074 1.87%
Bone Ash 11.61 Na2O 0.132 3.33%
FeO 0.254 6.40%
Black Iron Oxide 7.14

52. Seger Mol%
Bob’s Blue Matt
BOB'S BLUE MATT FH
KNO
CaO
0.316
0.021
9.01%
0.59%
MgO 0.009 0.25%
SrO 0.607 17.28%
Nepheline Syenite 53 Al2O3 0.410 11.68%
Tenn #10 Ball Clay 7 SiO2 2.097 59.74%
Silica 8 TiO2 0.004 0.10%
Strontium Carbonate 32 K2O 0.078 2.22%
Na2O 0.239 6.79%
Bentonite 2
CuO 0.045 1.29%
Copper Carbonate 2 FeO 0.002 0.07%

54. Bringle’s Green KNO
Seger
0.145
Mol%
5.7%
CaO 0.147 5.8%
Custer Feldspar 45.0 MgO 0.003 0.1%
Whiting 7.0 ZnO 0.248 9.8%
OM-4 Ball Clay 13.0 SrO 0.341 13.5%
Al2O3 0.222 8.8%
Strontium Carbonate 25.0 SiO2 1.286 50.7%
Zinc Oxide 10.0 TiO2 0.029 1.2%
Copper Carbonate 5.0 K2O 0.100 4.0%
Rutile 1.0 Na2O 0.045 1.8%
Red Iron Oxide 1.25 CuO 0.082 1.4%

56. Seger Mol%
Buttermilk KNO
CaO
0.15
0.47
3.5%
11.3%
MgO 0.39 9.3%
Gerstley Borate 9.63 Al2O3 0.20 4.9%
Dolomite 6.23 B2O3 0.12 2.9%
Whiting 8.25 SiO2 2.69 64.9%
ZrO2 0.13 3.2%
Custer Feldspar 26.88
TiO2 0.00 0.0%
EPK Kaolin 6.23 K2O 0.09 2.1%
Talc 12.38 Na2O 0.06 1.4%
Silica 22.11
Zircopax 8.25

58. Seger Mol%
Dependable Red KNO
CaO
0.249
0.503
6.1%
12.4%
Zinc Oxide 4.5 MgO 0.077 1.9%
ZnO 0.153 3.8%
Talc 3.5
Al2O3 0.302 7.5%
Whiting 13.0 B2O3 0.100 2.5%
Ferro 3134 10.8 SiO2 2.637 65.0%
F4 Feldspar 45.5 TiO2 0.001 0.0%
EPK Kaolin 5.2 K2O 0.067 1.7%
Silica 16.0 Na2O 0.182 4.5%
Bentonite 1.5 CuO 0.015 0.4%
Tin Oxide 1.0
Copper Carbonate 0.7

60. KNO 0.335 6.4%
Gail’s White CaO
MgO
0.224
0.436
4.3%
8.3%
Al2O3 0.627 12.0%
Custer Feldspar 57.1 SiO2 3.496 66.9%
EPK Kaolin 19.0 ZrO2 0.098 1.9%
Dolomite 9.5 TiO2 0.003 0.1%
K2O 0.230 4.4%
Talc 9.5 Na2O 0.105 2.0%
Zircopax 4.8

62. Seger Mol%
Laura’s Turquoise KNO
CaO
0.083
0.852
2.9%
29.7%
Al2O3 0.327 11.4%
SiO2 1.454 50.8%
Whiting 38.1 TiO2 0.084 2.9%
Custer Feldspar 23.8 K2O 0.057 2.0%
EPK Kaolin 28.6 Na2O 0.026 0.9%
Silica 9.5 CoO 0.005 0.2%
Copper Carbonate 3.1 CuO 0.056 2.0%
Cobalt Carbonate 0.25
Rutile 2.9

64. Seger Mol%
Mystery Blue KNO
CaO
0.228
0.738
4.3%
13.8%
Al2O3 0.382 7.2%
EPK Kaolin 10 SiO2 3.780 70.7%
Whiting 20 TiO2 0.185 3.5%
Silica 30 K2O 0.157 2.9%
Custer Feldspar 40 Na2O 0.071 1.3%
CuO 0.030 0.6%
Rutile 4
Copper Carbonate 1

66. KNO 0.157 5.5%
CaO 0.402 14.1%
Pier Black MgO
Al2O3
0.226
0.339
7.9%
11.9%
B2O3 0.030 1.1%
Custer Feldspar 42.7 SiO2 1.430 50.2%
EPK Kaolin 23.6 TiO2 0.002 0.1%
K2O 0.105 3.7%
Dolomite 23.6 Na2O 0.052 1.8%
Whiting 4.7 CoO 0.119 4.2%
Borax 5.4 FeO 0.094 3.4%
Cr2O3 0.048 1.7%
Cobalt Carbonate 6.6
Black Iron Oxide 3.2
Chrome Oxide 3.4

68. Seger Mol%
Rachel’s Blue KNO
CaO
0.302
0.650
5.9%
12.7%
MgO 0.006 0.1%
Al2O3 0.369 7.2%
Custer Feldspar 35
B2O3 0.200 3.9%
OM-4 Ball Clay 17 SiO2 3.557 69.3%
Whiting 12 TiO2 0.009 0.2%
Silica 19 K2O 0.140 2.7%
Na2O 0.162 3.2%
Ferro 3134 17 CoO 0.037 0.7%
Cobalt Carbonate 1.25

70. Seger Mol%
Rutile KNO
CaO
0.148
0.622
3.2%
13.5%
MgO 0.226 4.9%
Dolomite 15.8 Al2O3 0.370 8.0%
Custer Feldspar 30.0 SiO2 2.906 63.2%
Whiting 10.1 TiO2 0.321 7.0%
EPK Kaolin 17.8 K2O 0.102 2.2%
Silica 26.3 Na2O 0.046 1.0%
Rutile 8.0

72. Seger Mol%
Seafoam KNO
CaO
0.210
0.678
4.2%
13.6%
Al2O3 0.351 7.0%
Custer Feldspar 40 SiO2 3.471 69.5%
Silica 30 TiO2 0.170 3.4%
Whiting 20 K2O 0.144 2.9%
EPK Kaolin 10 Na2O 0.066 1.3%
Rutile 4 CuO 0.109 2.2%
Copper Carbonate 4

74. Seger Mol%
Speckled Lavender KNO
CaO
0.251
0.464
6.3%
11.6%
MgO 0.002 0.1%
ZnO 0.136 3.4%
Zinc Oxide 4.0
Li2O 0.075 1.9%
Lithium Carbonate 2.0 SrO 0.056 1.4%
Whiting 14.0 Al2O3 0.239 6.0%
Ferro 3134 7.0 B2O3 0.064 1.6%
Silica 20.0 SiO2 2.685 67.0%
K2O 0.150 3.8%
Custer Feldspar 50.0
Na2O 0.101 2.5%
Strontium Carbonate 3.0 CuO 0.013 0.3%
Bentonite 1.0 SnO2 0.018 0.46%
Tin Oxide 1.0
Copper Carbonate 0.6

76. Seger Mol%
Tenmoku KNO 0.180 4.4%
CaO 0.491 12.1%
Al2O3 0.296 7.3%
Custer Feldspar 43.4
SiO2 2.764 68.1%
EPK Kaolin 10.3 TiO2 0.001 0.0%
Whiting 18.3 K2O 0.124 3.0%
Silica 28.0 Na2O 0.056 1.4%
Red Iron Oxide 9.8 FeO 0.329 8.1%

78. Seger Mol%
Woo Brown to Blue KNO
CaO
0.223
0.603
4.5%
12.1%
MgO 0.004 0.1%
Whiting 18.0 Al2O3 0.348 7.0%
Custer Feldspar 42.0 SiO2 3.465 69.5%
TiO2 0.172 3.5%
OM-4 Ball Clay 13.0
K2O 0.154 3.1%
Silica 27.0
Na2O 0.069 1.4%
Red Iron Oxide 4.0 FeO 0.170 3.4%
Rutile 4.0

80. Seger Mol%
Yellow Salt KNO
CaO
0.322
0.318
9.3%
9.2%
MgO 0.233 6.7%
Al2O3 0.383 11.1%
Nepheline Syenite 200 61.0 SiO2 1.875 54.1%
Dolomite 20.0 ZrO2 0.206 5.9%
OM-4 Ball Clay 4.0 TiO2 0.002 0.0%
K2O 0.078 2.3%
Zircopax 15.0
Na2O 0.244 7.0%
Bentonite 1.0 FeO 0.127 3.7%
Red Iron Oxide 4.0

82. SiO2 Al2O3 B2O3 ZrO2 K2O Na2O CaO MgO FeO
GAIL'S WHITE 0.67 0.12 0.02 0.04 0.02 0.04 0.08
BUTTERMILK 0.65 0.05 0.03 0.03 0.02 0.01 0.11 0.09
YELLOW SALT 0.54 0.11 0.06 0.02 0.07 0.09 0.07 0.04

83. SiO2 Al2O3 B2O3 P2O3 TiO2 K2O Na2O CaO MgO Cr2O3 CoO FeO
3D BLACK 0.75 0.07 0.01 0.03 0.08 0.004 0.05
WOO BROWN TO BLUE 0.70 0.07 0.03 0.03 0.01 0.12 0.03
TENMOKU 0.68 0.07 0.03 0.01 0.12 0.08
TOMATO RED 0.65 0.08 0.02 0.02 0.03 0.08 0.05 0.06
PIER BLACK 0.50 0.12 0.01 0.04 0.02 0.14 0.08 0.02 0.042 0.03

84. SiO2 Al2O3 TiO2 K2O Na2O CaO MgO SrO ZnO CoO CuO FeO
MYSTERY BLUE 0.71 0.07 0.03 0.03 0.01 0.14 0.006 0.006
SEAFOAM 0.70 0.07 0.03 0.03 0.01 0.14 0.022
WOO BROWN TO BLUE 0.70 0.07 0.03 0.03 0.01 0.12 0.03
RUTILE 0.63 0.08 0.07 0.02 0.01 0.14 0.05
LAURA'S TURQUOISE 0.51 0.11 0.03 0.02 0.01 0.30 0.002 0.020
BRINGLE'S GREEN 0.51 0.09 0.01 0.04 0.02 0.06 0.13 0.10 0.033 0.01

85. SiO2 Al2O3 B2O3 SnO2 Li2O K2O Na2O CaO MgO SrO ZnO CoO CuO
DEPENDABLE RED 0.65 0.07 0.02 0.005 0.02 0.04 0.12 0.02 0.04 0.004
SPECKLED LAVENDER 0.67 0.06 0.02 0.005 0.02 0.04 0.03 0.12 0.01 0.03 0.003 0.003
A tiny bit of cobalt makes a big difference