Thread: JNAT Triboluminance:or Pizzaelectric Effect

Have any of you Jnat honers experienced triboluminance or Piezoelectric effect when honing with a Jnat or any other natural stones?

The other day while finishing a razor on a Nakayama kiita Iromono, I noticed when flipping at the end of a stroke a yellow/orange Triboluminance as droplets fell from the razor and hit the stone. The drop would light up and either dance across the stone to the edge on the sheet of slurry water, like a spark or break up into smaller droplets and then splayed out across the stone in random pattern like a firework.

The effect only occurred as the drop hit the stone.

I have never experienced this with any other stone, but have with this stone in the past. I don’t think I could photograph the effect, without a high-speed camera.

From what I can gather it is a Piezoelectric effect or Triboluminance and commonly seen as a parlor trick when crushing sugar candy, or striking two quartz crystals together.

I have not tried to reproduce the effect, with this or other stones and was wondering if it was this particular stone, slurry combination, the lighting or all three. The slurry was pretty thin.

Anyone else noticed this?

Marty-I have very little experience with JNats, having only owned a few Shoubodanis, but I watched in wonder as this happened when I honed on them. As I recall, the effect became more pronounced towards the end of a nagura progression as the slurry broke down finer and the tiny bubbles would race around like that. I thought that it had something to do with changes in surface tension, but that's probably over-simplistic. Part of me also thinks it might have something to do with charged particles as well, but more scientific minds could probably explain it better.

Either way, it is one of the more interesting phenomena I have encountered on a hone. (Great-now I want another JNat!).

As I am honing a batch of razors today, I often get into a contemplative/zen sort of mood (the kind where you just want to put some Chet Baker or Miles Davis on the blue-tooth and drag out every hone you've got lol!). In that vibe with my Chosera green brick over the sink, it just occurred to me that I have observed the same effect on my Zulu Grey, whose composition reminds me somewhat of a Jnat. After all, aren't both of a similar geological origin in that they are both sedimentary rocks created under enormous pressure on ancient sea-beds? In fact, my Zulu has the imprint of a fossilized piece of seaweed.

More food for thought. Now back to the sink.

edit: Okay, while finishing an edge at the sink it just occurred to me that I used to get the same effect on my PHIG, also a sedimentary rock (which I haven't used in awhile, though it's a very fine one that gives up awesome smooth edges). Time to get it out again and confirm.

New phenomenon to me. Sounds like we should start honing in the dark.

It is actually kind of cool.

The droplets look like molten steel when they hit the stone and shatter or shoot off the face of the stone to the edge. When they shatter, it is like a mini firework starburst the color of fire works, orangeish yellow.

Sounds amazing..

WE NEED PICS!

There's a lengthy discussion of this phenomena on Wikipedia:

https://en.wikipedia.org/wiki/Triboluminescence

And a whole bunch of stuff on Google, including videos:

https://www.google.com/search?sxsrf=...sclient=psy-ab

I have seen those images on line, What I see are not blue flashed they are orange yellow and it is the droplet as it hits the stone and I assume the reaction continues as the shock wave rolls across the wet stone to the edge or the energy of the wave decreases. The reaction is pretty long compared to the videos of smashed mints.

I expect the color is a result of the kind of crystal, most of the high-speed photography is done with candy, sugar crystals. There are some videos of quartz crystals rubbed together producing a similar color of yellow orange.

The cause is not fully understood but has something to do with the energy in the crystals as the partials collide and release energy on a molecular level. In this case a drop of thinned slurry colliding with the sheet of thin slurry on the stone face.

I will try to see if I can replicate it and take a video. I do not always see this, and I suspect it has a lot to do with this stone, the consistency of the slurry and the lighting. I was not homing in the dark, it was during daylight, in the shop with regular shop lighting.

I have tried several times to reproduce the effect, without success. I do not recall which Tomo I was using, I literally have a dozen on my bench and 4-5 that are the usual suspects, most frequently used.

I recall the slurry was thin, though do not recall how thin. Or if it was a blend of tomo, I often use a thin blend of Diamond and tomo, by thinning Diamond slurry and adding Tomo depending on the feel of the slurry and if I am polishing or resetting a jointed edge.

So, it may be difficult to re-produce intentionally. I have seen the effect several times, though never paid attention what may have cause it.

I am almost always experimenting finishing, though most of the process is similar, but constantly changing to keep interesting. Once you have a post 8k edge, it I easy to try new or different things and if it does not work, you don’t have to go back far, usually to Tenjyo slurry to refresh.

If I do see it, I will try to take a video.