Thread: Quartz in suji

Originally Posted by mainaman

does it scratch the bevels? or chip the edge? If not then it is not a problem, if yes you can try and dig it out.

I agree with this. The finish the stone makes is top priority, and not whether or not an uninvited guest that does no harm might be in it.

If the stone presents a weathered surface just about any mineral will have a gloss however even if not most minerals have some gloss to them. Really, more do than don't. Some of the most common minerals like calcite and feldspar can be white and they have gloss and can come in all colors of the rainbow too.

Originally Posted by thebigspendur

If the stone presents a weathered surface just about any mineral will have a gloss however even if not most minerals have some gloss to them. Really, more do than don't. Some of the most common minerals like calcite and feldspar can be white and they have gloss and can come in all colors of the rainbow too.

The crystallization process takes a lot of time as I'm sure you know, and, although, you are right, about every mineral having a gloss surface, most of their crystals are not visible on naked eye. The "innocent" types, like calcite do not scratch steel, but they also don't develop big crystals in this type of geologic formation, in Japan. For Jnats, iron and it's salts is the most annoying element and composition.

Originally Posted by Vasilis

The crystallization process takes a lot of time as I'm sure you know, and, although, you are right, about every mineral having a gloss surface, most of their crystals are not visible on naked eye. The "innocent" types, like calcite do not scratch steel, but they also don't develop big crystals in this type of geologic formation, in Japan. For Jnats, iron and it's salts is the most annoying element and composition.

When you say "crystal" do you mean the outward habit of the mineral or the internal latticework on a microscopic scale? You would need an electron microscope or better to see the latticework and in outward habit crystals are rare period. Some more so than others. Unless you see some facets of the xtl you might not even know if you have one or just the massive mineral.

I know that you are very knowledgeable in geology/mineralogy, and my knowledge is limited. On my previous post, I included both types, as a general definition of the word "crystal".
But in that case, it appeared to me unlikely for a non soluble mineral, even slightly, to be present there in the form of a "shiny", non amorphous, inclusion, as, from what I have read, the inclusions in Jnats are generally formed from soluble "salts" that penetrate those naturally formed cracks that appear in the stones, like the ones in the above photo. With the water vaporizing, or dispersing by any means, some of those salts remain in the cracks, and with repeating cycles of this, and time, heat, with some reactions, the toxic inclusions are formed.
Again, I'm by no means an expert, as you can see, but it's a topic that interests me.

Shiny things in lines are generally bad, but if they're fine, they can be non-toxic and should be ignored. As said before, just make sure it isn't scratching the bevel if you're honing on it. I have some hones with them that I ignore, and larger ones have to be picked out as Ilzuka-San at Shigefusa did with his suita.

What these lines actually are is a layer of kawa skin, and if you were to lap down to one from the side as I have done with a small piece, you'll find that it is very hard. The sandpaper or plate almost stops cutting. Still. if it's very fine, it will just get worn down with the rest of the stone and and won't pose an issue. If it's large enough to resist wearing with the rest of the stone, it's likely to be a problem.

Here's a couple of images of a piece of nagura, it actually broke in shipping, but it illustrates what these lines really are well.

Cheers, Steve

Oh, BTW, if you choose to pick out the inclusion, use a carbide stylus and don't drag the tip along the line. The best way is to push the stylus tip straight down on the inclusion until it fractures, and continue doing so until it looks like a series of edge-to-edge dots on the inclusion and the inclusion is now below surface. Then you can very lightly dress the edges of the line with the stylus to keep it from shedding particles.

Cheers, Steve

I never saw those posts about shigefusa. I like his interpretation of stones, especially for knives where it is practically useless to prepare a knife with a super fine stone.

He's running a business, too, so maruka stamps on fine stones don't mean anything to him (I don't find much value in them, either, but I'm not a collector).

I like his comment about not needing nagura because of the jigane. I find that true on suitas with tools, also, which makes them really nice to use. My favorite suita were all less than $250.