W.A fossicking

Does any one know of anywhere I can go check out I'm just south of Perth.
Look not out to make it rich or steal any one's secret spots just after some pretty rocks .
Kid friendly would be good as well but not necessary.
Also very new at this so hints to help with what areas are good to look around (river bed , rock out crop , or something else entirely..)
Thank you in advance

If you click on the link below and then on the red button marked "DOWNLOAD PDF" near the bottom of the linked page, you'll eventually get to a freely downloadable copy of Mineral Resources Bulletin 25, Gemstones of Western Australia, all 328 pages of it! More info than you could ever want or need, I'd suspect:

http://www.dmp.wa.gov.au/Gemstones-of-Western-Australia-1653.aspx

TL;DR: There's little or nothing of interest that's conveniently near Perth and surrounds - the geology is no good for 'pretty rocks'.