Category: Glaze > Iron > Oil Spot
Created 2017-10-04 09:33:52 by Pieter Mostert
Categories: Glaze > Iron > Oil Spot
Firing Temperature: Δ9-10
Atmospheres: Reduction
Surface Type: Glossy
Transparency: Opaque

A glaze from chapter 10 of Joseph Grebanier's book "Chinese Stoneware Glazes".

Described as having "a rich brown background color; a somewhat fatty, glossy texture full of rather large bubbles and covered with very tiny, healed-over pitmarks; and a cerulean blue 'oil spot' effect collecting in hundreds of these little pits."

According to Grebanier, it must be applied soon after mixing, and use on a body high in silica results in dunting.

Material Amount Batch Subtotal
Maine feldspar 66
Silica 12
Softwood ash 10
Whiting 8
Georgia Kaolin 4
Total Base:100
Yellow Ochre 10.5
Total: 110.5

Percentage Analysis

Ingredient Amount SiO2 Al2O3 MgO CaO K2O Na2O KNaO P2O5 Fe2O3 TiO2 MnO LOI
Maine feldspar6646.8311.420.070.135.361.867.220.33
Softwood ash100.20.824.
Georgia Kaolin42.111.780.
Yellow Ochre10.
100% no LOI 64.8214.750.878.456.231.878.10.452.250.060.24

Unity Molecular Formula (UMF)



0.11 Na2O
0.25 K2O
0.56 CaO
0.08 MgO


0.54 Al2O3


4.01 SiO2


0.05 Fe2O3
0.01 MnO
0.01 P2O5





0.36 : 0.64

SiO2:Al2O3 Chart

Closest 27 neighbors in Glaze > Iron > Oil Spot.

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Stull Chart
SiO2:Al2O3 Ratio
SiO2:Al2O3 Ratio 7.46

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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
Whiting Harmful WARNING Causes eye irritation
Yellow Ochre Health Hazard DANGER May cause cancer.