I know that, and I'm thinking it may be chalcedony seems very fine particles. Just wanted another opinion. Have a lot of it. Was told blue quartz, but too fine I think.
What region did you find this in? Looks like Opal to me, could also be chalcedony. I'd be curious about how the play of light is...change colors, show "chatoyancy", translucent, transparent or generally opaque? Might be hard to tell the transparency with the amount of host rock tho...
Never heard of quartz of any kind occurring blue naturally which leads me to think Opal but I'm no pro