Some great looking rocks you have there, and the rocks at the bottom of the second photo are exactly the type I am after. Would love to know the general area these were found in and perhaps go for a bit of a hunt myself.
Anyone wanting to find rocks would be well served doing a bit of research at the local library or contact a local lapidary group. I fossick for gemstones on the New England Tableland around Glen Innes/Inverell and have found checking out old books on gem fossicking is a valuable resource. Many newer books have very limited information on where to fossick. Tin and gold mining was done by dredging streams of all material and leaving the spoil beside stream or deposit. These areas can be rich hunting places. Gem Shows that include car boot sales like those at Lismore, Glen Innes, Armidale etc are another likely source.
There is a little book called 'Where to find Australian Gemstones' by Derrick & Doug Stone.......I kid you not! Another great book is 'How & Where to find Gemstones in Australia and New Zealand' by Bill Myatt. The other useful publication to use is 'Fossickers Guide: discovering the earth's riches' by Mineral Resources NSW. Buying secondhand books on Ebay is often the easiest path. Don't overlook quarries and earthworks like cuttings that frequently have rocks roll off into the drain.
Yes I'm planning to dabble in a bit of penjiing with some of the rocks but I'm mainly interested in something like saikei. I have some colorado spruce and I'm goingto have a go at a wind swept mountain peak by using casting resin to join several rocks together. The blues of the spruce with the whites of the quartzs should evoke the look of a freezing winter. I'm after. I have a rock saw so I can cut a flat on a rocks so they are stable also. Inaddition I also found these rocks that would make a coral reef/island saikei