What are the idioms about the word furnace?

『Mastery』

『Pinyin』

lú

huǒ

chún

qīng

『First Pin』

lhcq

『Interpretation』

Pure and pure. When Taoist priests make alchemy, they believe that it is a success until the furnace emits a pure blue flame. ◇ It is used to describe the state of mastery and perfection in kung fu.

『Kangxi Dictionary』

Lu, fire, pure, green.

『Source』

Tang Dynasty Sun Simiao's "Four-Character Poetry" The fire in the furnace is blazing, and the flames are bright; the smoke reaches Guizhou, and the flames are not fake. ”

『Example』

Now, the climate has reached ~, it is the time for brothers to show their talents. ★Qing Dynasty·Zeng Pu's "Niehaihua" Chapter 20 Five times