Bruce Hoadley's book is the best resource I know of for wood identification for ordinary folks. Identifying Wood by Bruce Hoadley

A pic would be better, tbh.

A lot of coniferous woods get a fungus condition called Blue Stain which can appear as gray streaks.

Spalt(ed) maple is another fungal infestation of wood but is usually a sharply-delineated black ring within the wood.

I'm sure there are others.

Some woods are naturally sort of gray, like lauan and chestnut. Lauan also has pink in it, and chestnut more like oak otherwise.

Casey

A pic would be needed at least.Also the part of the world would help.

There are different parts of the country and world that have different soils with different minerals that trees pick up over the ages that can cause streaking or deposits of all kinds.

thank you all

Sounds like blue-stain pine