In June, my sister Helen and her grandson Sam came with me on a visit to Gemstone Beach. Sam spent a lot of time climbing the small slumps of mud at the bottom of the beach’s cliffs, but he also played along the stretch of beach and collected a few stones alongside Helen and myself.
Later, I sorted through Sam’s stones and brought 15 home with me to tumble polish. That process has now been completed. These are Sam’s stones:
The second stone is a particularly colourful sedimentary stone, with light and dark layers. In a drawer in the rock display area of the Riverton Museum is a similar stone identified as banded argillite:
The third stone, a green one, perhaps argillite or some other mudstone, has a lacy network of light green lines over its surface:
The fifth stone, a kind of breccia (containing smaller sharp-edged stones in a matrix), is mainly light-coloured on one side and dark-coloured on the other:
“Porphyry” is the term given to the eighth stone. It has a volcanic origin, with crystals within it which have grown as the hot rock cooled:
The tenth stone is my favourite. Though only a small stone, it has a fascinating texture, with smooth parts of clear silica and iron-stained semi-fibrous sections:
The fourteenth stone is an interesting one – grey on both sides but a lighter-coloured layer pressed in the middle, exposed around the edges:
And the fifteenth stone is a small conglomerate (containing smaller round-edged stones in a matrix):
The first half of the rest of Sam’s stones:
The second half of the rest of Sam’s stones:
I started to tumble polish these stones in a three pound barrel on 21 June, and the process was completed just over five weeks later on 28 July (the tumblers were inactive for a week during this time when electrical work was being undertaken on another project). Initially, the stones were tumbled in 320 silicon carbide grit for seven days, followed by a two hour tumble in soap. Then a pre-polish tumble in tin oxide took place for just under five days, followed again by a two hour soap tumble. The pro-polish tumble in a finer tin oxide lasted for seven days, with the final step being a five day burnishing tumble in borax. Sam’s stones were tumbled with other stones collected by Helen, in order to make up a full batch.
Wow! Sam is super excited to see his stones. Thanks so much for taking the time to tumble for him. He definitely has an interest in looking for and collecting stones now
You’re welcome! It might keep Sam out of the mud for some of the time when he is down at Riverton…