Category: Glaze > Purple
Created 2017-10-08 17:15:26 by Sid Henderson
Categories: Glaze > Purple
Firing Temperature: Δ9-10
Atmospheres: Reduction
Surface Type: Glossy
Transparency: Opaque

A copper-purple glaze with beautiful variegation. Its a little runny, so apply it with care, aiming for about the thickness of a credit card on the top 3/4ths of the piece and a bit thinner on the bottom 1/4th.

Material Amount Batch Subtotal
Custer Feldspar 46
Silica 20
Colemanite 13.5
Whiting 8
Dolomite 6
Zinc Oxide 4
EPK 2.5
Total Base:100
Bentonite 2
Tin Oxide 1
Copper Carbonate 1
Cobalt Carbonate 0.5
Rutile 0.5
Total: 105

Percentage Analysis

Ingredient Amount SiO2 Al2O3 B2O3 MgO CaO ZnO K2O Na2O KNaO P2O5 Fe2O3 TiO2 CoO CuO SnO2 LOI
Custer Feldspar4631.517.820.144.61.385.980.050.14
Zinc Oxide44
Tin Oxide11
Copper Carbonate10.640.36
Cobalt Carbonate0.50.320.19
100% no LOI 57.249.737.291.4410.814.254.921.536.450.010.20.490.330.681.06

Unity Molecular Formula (UMF)



0.07 Na2O
0.15 K2O
0.15 ZnO
0.54 CaO
0.1 MgO


0.27 Al2O3
0.29 B2O3


2.67 SiO2
0.02 SnO2
0.02 TiO2


0.01 CoO
0.02 CuO





0.22 : 0.78

SiO2:Al2O3 Chart

Closest 58 neighbors in Glaze > Purple.

Click and drag to zoom
Stull Chart
SiO2:Al2O3 Ratio
SiO2:Al2O3 Ratio 9.96

Similar Base Recipes

No recipes with similar base ingredients and amounts were found.

Similar RO/R2O Unity Formulas

No recipes with similar RO/R2O Unity Formulas were found.

Alexander Kuttel 2017-12-09 01:10:48
Great glaze! Red-violets are somewhat hard to come by, but this glaze has become very popular since our first test of it. It will begin to run at 10 though.


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
Custer Feldspar HarmfulHealth Hazard WARNING May cause damage to lungs through prolonged or repeated inhalation.
Suspected of causing cancer through
prolonged or repeated inhalation.
May cause allergy or asthma symptoms or breathing difficulties if inhaled.
May cause skin or eye irritation.
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
Whiting Harmful WARNING Causes eye irritation
Dolomite Health Hazard DANGER May cause cancer (Inhalation) 1 0 0 E
Zinc Oxide 0 0 0 *
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
Bentonite Harmful WARNING Causes eye irritation
Causes skin irritation
May cause respiratory irritation
Tin Oxide Harmful WARNING Harmful if swallowed.
Copper Carbonate Harmful WARNING Harmful if swallowed.
Causes skin irritation.
Causes serious eye irritation.
Cobalt Carbonate Health HazardEnvironmental Hazard DANGER May cause cancer
Suspected of causing genetic effects
May damage fertility or the unborn child
May cause allergy or breathing difficulties if inhaled
May cause a allergic skin reaction
Very toxic to aquatic life
Very toxic to aquatic life with long lasting effects
2 0 0 *
Rutile 1 0 0