Mahavir is a potassium (potash) Feldspar imported from India.
Mahavir is used as a replacement potassium feldspar since Custer Feldspar is no longer being mined as of 2024
Custer has slightly more silica, so a 1:1 substitution may cause changes in glazes.
An approximate substitution for Custer:
90.5% Mahavir Feldspar
6.5% Silica
3% EP Kaolin
Mahavir is naturally thixiotropic.
Pure Mahavir can be suspended in water with a ratio of 100g Mahavir to 70g water. It still settles quite quickly though. This can be fixed with some Bentonite or Epsom Salts
Glazes low in clay should see improved dipping applications if Custer Feldspar is substituted with Mahavir.