Category: Glaze > Blue > Cobalt
Created 2017-10-21 21:08:40 by Sid Henderson
Categories: Glaze > Blue > Cobalt
Firing Temperature: Δ10
Atmospheres: Oxidation, Neutral, Reduction
Surface Type: Glossy
Transparency: Translucent

This is a glaze I created based off the recipe "Winn Blue".

I was interested in creating a very stable, hard, and deep blue colored glaze with a minimum of Cobalt.

I was fortunate enough to acquire black cobalt oxide from china, which is actually one of the best cobalt pigments I've ever worked with.

Dolomite and sodium were both used in order to push blue towards a brighter, purple-blue color.
Calcium and a small amount of strontium serve as additional color enhancers.

Material Amount Batch Subtotal
Kona F-4 feldspar 44
Silica 18
Dolomite 10
Wollastonite (Theoretical) 9
Kentucky OM #4 Ball Clay 9
Strontium Carbonate 2
Total Base:100
Bentonite 2
Cobalt Oxide 0.5
Total: 102.5

Percentage Analysis

Ingredient Amount SiO2 Al2O3 MgO CaO SrO K2O Na2O KNaO P2O5 Fe2O3 TiO2 CoO LOI
Kona F-4 feldspar4429.378.620.020.752.
Wollastonite (Theoretical)94.664.34
Kentucky OM #4 Ball Clay94.972.510.
Strontium Carbonate21.40.6
Cobalt Oxide0.50.470.03
100% no LOI 65.4315.362.438.681.492.383.315.690.

Unity Molecular Formula (UMF)



0.17 Na2O
0.08 K2O
0.05 SrO
0.5 CaO
0.2 MgO


0.49 Al2O3


3.54 SiO2
0.01 TiO2


0.01 Fe2O3
0.02 CoO





0.26 : 0.74

SiO2:Al2O3 Chart

Closest 87 neighbors in Glaze > Blue > Cobalt.

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Stull Chart
SiO2:Al2O3 Ratio
SiO2:Al2O3 Ratio 7.23

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09/2016 Note: This is a new feature. If a recipe material is not listed, that material's data has not yet been added. Some materials only have GHS ratings, while others only have HMIS ratings. Warnings differ between systems and countries. Glazy does not take any responsibility for accuracy of linked SDS information. Contact your ceramics supplier for safety information for your specific materials.
Globally Harmonized System (GHS) Hazardous Materials Identification System (HMIS) SDS Link
Material Pictograms Signal Word Hazard Statements Health Flammability Hazard Protection
Silica HarmfulHealth Hazard DANGER From 200-Mesh SDS:
May cause cancer by inhalation.
Causes damage to lungs through prolonged or repeated exposure by inhalation.
* 0 0 E
Dolomite Health Hazard DANGER May cause cancer (Inhalation) 1 0 0 E
Wollastonite (Theoretical) Health Hazard DANGER Vansil W-30 Wollastonite SDS:
May cause cancer if inhaled.
Causes damage to organs through prolonged or repeated exposure if inhaled. (respiratory tract)
Kentucky OM #4 Ball Clay Health Hazard WARNING May cause damage to lung through prolonged or repeated inhalation 2 0 0 E
EPK HarmfulHealth Hazard DANGER EPK Kaolin is a naturally occurring mineral, which may contain amounts of crystalline silica
typically 0.1-1.0%, may cause damage to respiratory system through prolonged or repeated
1 0 0 E
Strontium Carbonate Harmful WARNING Product dust may be irritating to eyes,skin and respiratory system.  1 0 0 E
Bentonite Harmful WARNING Causes eye irritation
Causes skin irritation
May cause respiratory irritation
Cobalt Oxide HarmfulHealth Hazard WARNING Suspected of causing cancer
Harmful if swallowed
May cause allergy or breathing difficulties if inhaled
May cause an allergic skin reaction
2 0 0 *