Batch 26 is a special batch because it only contains hydrogrossular garnets that I’ve found on Gemstone Beach in Orepuki, Southland. It just so happens that Gemstone Beach is about a 25 minute drive from where I live so I’m extremely lucky to have this place literally on my doorstep!
I’m also incredibly fortunate to know a very knowledgeable fossicker (whom I like to call JP) who taught me how to spot the hydrogrossular garnets on Gemstone Beach. At the start of my learning journey I’d be picking up quartzites and mistaking them for the hydrogrossulars. With a little practise (and a lot of patience from JP) I eventually got the hang of spotting them correctly! Hydrogrossulars are waxy to the touch and once you recognise them they are easy to spot.
JP has many informative blog posts on hydrogrossulars particularly this one on why they are found at Orepuki (and hardly anywhere else in the Southland Island) and more recently this one detailing the various kinds of hydrogrossular garnets. All JP’s posts on hydrogrossular garnets can be found here.
Most hydrogrossulars can skip Stage 1 (80/100grit) and Stage 2 (220grit) which is exactly what Batch 26 has done. I started them off at 400grit.
Batch 26: 3lb Tumbler 1
Stage 3: 400grit
Number of Stones: 36
Weight in: 664g
4 Tbspns of 400grit – pellets added
Days Tumbling: 8
Weight out: 635g – loss of 29g
Stage 3 Repeat: 400grit
Number of Stones: 36
Weight in: 635g
4 Tbspns of 400grit – pellets added
Days Tumbling: 7
Weight out: 555g – loss of 80g
Most of the hydrogrossulars weren’t smooth enough after the first 400grit tumble so I decided to put them through 400grit again. At the end of the second tumble I removed one of the hydrogrossulars and put it in the redo holding box as it wasn’t ready to go through with the others to polish and burnish.
Batch 26: Pre-tumble
Batch 26: After first 400grit
Transfer to 4lb Tumbler
The 35 hydrogrossular garnets of this batch (26) have joined Batches 24, 25 & 28 in the 4lb tumbler for polishing and burnishing. It’s a pretty full tumbler and I’m hoping that it’s not overfilled. In reflection, I wish that I had weighed the hydrogrossulars separately after the polishing was complete just to see how much had been ground away.
Stage 4: Polish Mix
Number of Stones: 146 + 35
Polish Mix (2nd use): 9 Tbspns of polish mixed with 600mls of clean water. Pellets added.
Days Tumbling: 10
Stage 5: Burnish
2 Tbspns of Borax to clean and clear any remaining polishing mix. Pellets added.
Days Tumbling: 2
Polished Stones of Interest: Batch 26
Batch 26 | 3lb Tumbler 1 | Hydrogrossular Garnets from Gemstone Beach | 17 August – 7 Sept
4lb Tumbler | Batch 26, 24, 25 & 28 | Mostly Gemstone Beach | 15 Sept – 27 Sept 2023
The hydrogrossular garnets are a little different from other stones – I don’t think they need as much tumbling. The slurry is also different – a very fine milky liquid. It looks like your polishing worked well!
Thanks JP! I’ve got quite a little collection of beautiful looking hydrogrossulars now!