A dense clay body fired far hotter than terracotta. Where terracotta stays soft and open, stoneware becomes hard, heavy for its size and rings when tapped.
Quality & testing
What “unglazed vitrified stoneware” means, and how we check it.
Three words carry the whole promise of a Parables piece. Here is what each one means, and the test every firing has to pass before anything leaves the kiln shed.
The words
Three words, one promise.
Fired until the clay begins to fuse into a glass-like body. The pores close, so the piece does not drink water, hold an odour or seep. Nothing is added to seal it: the kiln does it.
No glaze, paint or coating. What you drink from and touch is the fired clay itself, so there is no glaze to craze, chip or leach, and the colour is the colour of the firing.
Our test
Every firing is boiled for three hours.
A vitrified body should not take in water, even after hours in it. So we test for exactly that, on every batch that comes out of the kiln, before any of it is packed.
We take samples from the front row and the last row of every shelf, where the heat in the kiln differs most, and boil them for three hours.
If a sample from any shelf fails, the whole shelf is fired again and retested. Nothing from that shelf is sold until it passes.
More about the material
Batch testing, step by step
From kiln to box.
- 01
Firing
Each batch is fired until the body vitrifies.
- 02
Sampling
Samples are taken from the front and last row of every shelf.
- 03
Boil test
The samples are boiled for three hours.
- 04
Pass or refire
A shelf passes only if all its samples pass. Otherwise the whole shelf is refired and tested again.
- 05
Finishing
Passed pieces are inspected, stamped with our mark and packed by hand.
Try it yourself
Watch a cup take the boil test.
Pick one of the six cups from our kiln log, or a terracotta cup for comparison, and run the test: weigh it dry, boil it for three hours, weigh it again.
- Weigh it dry—
- Boil for three hours—
- Weigh it again—
From our kiln log
What our testing shows so far.
Shared as information from our own internal testing. It is not a certification or a laboratory report.
Under 1.5% — limit of our in-house method.
Six cups were weighed dry, boiled for three hours and weighed again. Four showed no measurable gain at all. The other two took in 1 g and 2 g, about 0.7% and 1.4% of their weight.
Terracotta and earthenware typically absorb 10% or more.
2,475–3,600 Hz
We suspended pieces, tapped them and recorded the sound. Each one rings with its own clear, steady note, and the same note every time: one cup, tapped 14 times, gave the same pitch with essentially no scatter.
Every piece was still ringing at close to full strength 300 ms after the tap. None gave the dull thud of a porous body.
| Cup | Dry (g) | After boiling (g) | Water taken in | Result |
|---|---|---|---|---|
| 1 | 143 | 144 | about 0.70% | Vitrified |
| 2 | 142 | 144 | about 1.41% | Vitrified |
| 3 | 113 | 113 | <0.44% | Vitrified, impermeable |
| 4 | 136 | 136 | <0.37% | Vitrified, impermeable |
| 5 | 111 | 111 | <0.45% | Vitrified, impermeable |
| 6 | 129 | 129 | <0.39% | Vitrified, impermeable |
Weighed to the nearest gram, so “no change” means less than one gram: the “<” figures are the most that could have gone unseen.
What it means for you
Ready to use, from the box.
No preparation. Wash it and use it.
Only fired clay touches your food and drink.
It will not seep, soften or hold an odour.
Clay dug and processed within Manipur.
Enquire
Wholesale, gifting and bespoke orders.
Tell us what you need and we'll come back with quantities, lead times and pricing.
Contact
Nurakhudonglei Private Limited
Thoubal, Manipur 795138, India