Batch 81 : How Breccia Differs from Conglomerate

Breccia (pronounced bre-CHE-a) is a funky type of sedimentary rock that’s actually composed of large angular broken fragments of other rocks that get cemented together by compression. Gemstone Beach (my local rock-hunting ground) is a source of many sedimentary rocks!

Breccia and conglomerate are very similar rocks. They are both clastic sedimentary rocks composed of particles larger than two millimetres in diameter. The difference is in the shape of the large particles. Conglomerate particles are rounded.

Easy right! Breccia = angular fragments. Conglomerate = round particles! Yeah nah! As JP mentions in his post here, angular doesn’t always mean brecciated because igneous rocks (remember igneous rocks are formed from melted rock deep inside the Earth) can have angular fragments too but not be breccia!

IMG_4402
Conglomerate example – Slope Point

The stones in Batch 81 have come from the Gemstone Beach redo drawer. 31 are formally from Batch 74 (needed a redo), 8 were from Batch 73 that weren’t ready for polish, 7 from Batch 71 (mainly hydrogrossulars) that needed a redo, 9 from an unnumbered batch in the 3lb tumbler 4 that were ready for 220grit and 2 that were just in the drawer waiting for a batch to start Stage 2.

Also doing a tumble in this batch are some slices from some stones that I recently had a go at cutting. I’m looking forward to turning those ones into necklaces so I hope they tumble well and take a good polish.

Batch 81: 4lb Tumbler 2

Stage 2: 220grit

Number of Stones: 31+8+7+9+2=56
Weight in: 1042g
4 Tbspns of 220grit
No Borax added
Small ceramic media added
Days Tumbling: 10
Weight out: 873g – loss of 169 grams

Transfered to 3lb Tumbler 4: Stage 3: 400grit

Number of Stones: 52
Weight in: 885g
3 Tbspns of 400grit
1 Tbspn Borax
Ceramic media added
Days Tumbling: 12
Weight out: 792g – loss of 93 grams

Pre-polish Soap Tumble

Number of Stones: 52
2 tspns of grated sunlight soap.
Same ceramic media added
Time: 4 hours

Batch 81: Pre-Tumble

4lbT1
What started out in the 4lb Tumbler

Batch 81: After Stage 3

B81 Stage 3
What ended up in the 3lb Tumbler for polishing

Ready to Polish

Stage 4: Polish Mix

Number of Stones: 52
Weight in: 792g
Polish Mix (2nd use): Already mixed and used once before.
Plastic Pellets added for cushioning
Days Tumbling:
Weight out: 789g – loss of 3 grams

Polish Complete
Batch 81 complete
Batch 81 tumbled and polished

Polished Stones of Interest: Batch xx

B81 SOI
A: A really good breccia example – not found a stone like this before
B81 SOI
B: These pink ones are really hard to get to take a shine! Gorgeous quartz vein – thulite is pink
B81 SOI
C: Brecciated jasper floating in quartz
B81 SOI
D: Cute little sedimentary (mudstone) with quartz veins
B81 SOI
E: Photo does not do this justice – it more orangey in RL
B81 SOI
F: Such a cute stone! I just love it!
B81 SOI
G: Such an interesting quartz-veined small stone! Polished well.

Batch 81 | 4lb Tumbler 2 | Gemstone Beach | Early August – 5 September
3lb Tumbler 4 | 22 September – 18 October 2024

Leave a Reply

Your email address will not be published. Required fields are marked *