We regularly sell Scottish galaxy stones online here at the Stone Circle. Most of the galaxy stones for sale here are smaller. We choose them for variety of colour and for sizes that we can easily post. This one is two fingers sized. We ship internationally, too.
This Basalt and agate rock formed when bubbles rose through slow cooling lava. The rainwater gradually filled in the bubbles with crystallisation over time. It's fun stuff known by its real name: Amygdaloidal Basalt. Technically we ought to through the word vesicular in there, since the vesicles are the little holes the bubbles form in.
I believe this is an Ayrshire one but I brought a bunch back from Angus recently, so it may be from here.