A coarse, crumbly flat black powder.
No they had flammable substances but not gunpowder. MistroJoe
Gunpowder was invented by the Ancient Chinese. Gunpowder came to Europe in the 1260s.
Ancient Romans did not use gunpowder. Gunpowder was invented by China around the middle ages.
What did the Ancient Greek Theatres look like?
gunpowder is made from sulphur, charcoal, and salt peter. This makes the color dark grey to black depending on the exact mix.
Fireworks.
Ancient Chinese
gunpowder fireworks silk
Used by the Ancient Chinese for fireworks.
There are various forms of gunpowder. Black powder can be clumpy or powdery, ranging from black to light gray depending on the actual mixture. See the related links below for some views of gunpowder.
The ancient Greeks did not possess gunpowder. So the answer is no.
Make firecrackers