Garden Railway Forum

I have no idea about Irish ballast, but you are right yours does look a bit bright. However, I think you'll find that once the windblown soil gets in there and the moss starts growing it will tone down nicely. If you want moss to grow, try sprinkling natural yoghurt over it. It looks a bit odd to start with but does grow moss well once it gets going.

My understanding is that real ballast is made of crushed rock with rough edges to allow it to interlock together. Polished stone is not suitable for this purpose and so looks out of place, apart from the colour and reflective surface.
You have a wonderful collection of natural stone so why not choose a suitable colour and spend some time crushing it to the correct size. I had to resort to that option myself, but it pays off in the end.
A steel tube (post rammer) and heavy steel rod is all that's needed, and it lets off lots of frustration!

Are there any pet stores you can visit? I've found them useful for materials in various scales. For this, maybe fish tank gravel? Chicken grit is usually nicely angular but can be a bit dubious on the colour front and maybe too small.

Or garden centres, especially items like horticultural/alpine grit?