Ol Doinyo Lengai ( en.wikipedia.org )
...the lavas of Ol Doinyo Lengai have temperatures of 540–593 °C (1,004–1,099 °F); they are so cold that during the day they look like mudflows or oil and glow only during the night.
![](https://mbin.grits.dev/media/cache/resolve/entry_thumb/9b/b1/9bb1ff2546212eac7dcac5b7378fa12e94ce9a9032041a4cc62413b42528cea1.jpg)
...the lavas of Ol Doinyo Lengai have temperatures of 540–593 °C (1,004–1,099 °F); they are so cold that during the day they look like mudflows or oil and glow only during the night.