The crystals that form as this cone 6 fluid-melt glaze solidifies are one of the minerals in the recipe: Spodumene. Actually β-spodumene. But it is so expensive, and there is 42% here! What would it take to reduce the cost of making this glaze ($52/kg in 2026)? Another flux could certainly make it just as melt-fluid, but would not grow spodumene crystals.
β-spodumene is Li2O - Al2O3 - 4SiO2 So the 0.22 Li2O in this glaze would require 0.22 Al2O3 and 0.88 SiO2 to crystallize as a β-spodumene-type lithium aluminosilicate. The glaze contains 0.24 Al2O3 and 1.41 SiO2. There is almost exactly enough lithium to combine with nearly all of the alumina as β-spodumene. The 2% rutile supplies TiO2; it acts as a nucleating agent. Replacing Li2O with another flux could maintain the melt fluidity, but Na2O, K2O or B2O3 cannot simply take the place of Li2O in β-spodumene.
It is possible that less spodumene could still do this. That could be tested by reducing Li2O to 0.1 and increasing Na2O to 0.23 (while maintaining the other oxides as-is). B2O3 could also be tried (it has a far lower thermal expansion). Of course, effecting changes in specific oxides requires some glaze chemistry (e.g. in an Insight-live.com account).

This picture has its own page with more detail, click here to see it.
Lithium carbonate is now ultra-expensive. Yet the reactive glaze on the left needs it. Spodumene has a high enough Li2O concentration to be a possible source here. It also has a complex chemistry, but the other oxides it contains are those common to glazes anyway. Using my account at insight-live.com, I did recipe rescue calculations and got a pretty good match in the formulas (lower section in the green boxes). Then I made 10-gram balls and did a GLFL test at 2200F (notice the long crystals in the glass pools below the runways).
Not surprisingly, this recipe is very runny; that's why the tiny yellow crystals grow during cooling. The new version fires very similarly, perhaps better. Our calculated cost to mix this recipe in 2022 was $17.84/kg vs. $10.40/kg. In 2026 it is triple that! But there is a practical cost: Poor slurry properties. The spodumene sources so much Al2O3 that 70% Alberta Slip had to be dropped to accommodate it! How does one use this type of glaze without ruining kiln shelves? Using a catcher glaze is one answer.
![]() PayPal | No tracking, No ads, No paywall, No transient content! Just organized, concise information constantly updated and improved. Was this helpful? Consider supporting me. |
Buy me a coffee and we can talk