It burns with a smokeless blue flame that is not always visible in normal light.

A great, jagged wall of rock seemed to blaze with smokeless flame.

The fierce gout of smokeless flame grew rapidly.

Whatever the torches were made of, they burned with a clear, relatively smokeless flame and a faintly aromatic scent.

Then it caught with a weak blue smokeless flame.

All but isopropanol burn with a smokeless flame; it can provide both light and heat.

On the walls, the torches burned smokeless flames of magic.

The silent, smokeless flame cast harsh shadows around the circular room.

It was a smokeless blue flame, waist high, sprouting directly from the ground.

Each burned with a nearly smokeless, yet very bright, flame.