"Bone ash?"
Shen Le blurted it out. The moment the words left his mouth, his whole body shuddered, and every hair on his back stood on end:
He had considered bone ash as an answer before. This packet of powder did not resemble plant ash, Titanium White Powder, calamine, gypsum, or any other kind of white mineral powder he had handled;
The powder was not particularly fine. It felt rough and prickly to the touch, and upon closer inspection, it seemed to have a faintly flaky texture;
Of course, there was also visibly mixed-in stone powder. That could not be helped. Under ancient conditions, it was impossible to grind it up without bringing in some other impurities.
Besides, bone ash was not an especially rare material—from the perspective of later generations, it had been added when firing ash porcelain and low-temperature lead-glazed pottery, such as Tang Sancai and Ming Dynasty and Qing Dynasty glass glazes.
Not to mention bone china, which used over 25% bone ash in its porcelain body. The resulting porcelain was fine and thin, smooth and warm as jade...
Yet Shen Le had not immediately experimented with bone ash, mainly for two reasons. First, the reason bone ash was used for low-temperature lead-glazed pottery was precisely because it could not withstand excessively high temperatures:
In a reducing atmosphere at high temperatures—above 1250°C—calcium phosphate could easily decompose, causing the glaze to yellow, blister, or develop pinholes, making it impossible to fire a pure white glaze.
Second, the bone ash available now looked far too coarse to Shen Le. If it was not ground finely enough, it would not be uniform during firing, its reaction with the other glaze materials would be incomplete, and the result would easily come out patchy...
But now, as Shen Le stared at the