Thread: Has Anyone Ever Honed With a Lydian Stone?

Originally Posted by Geezer

So, either way we win!
Thank you!
~Richard

You are absolutely correct Richard!
Maybe not when I look on the prices for the stones of the webside that is mentioned here. But a black ark is a fantastic finisher and even if the Lydian stones really exist as a single species - it will be hard to beat a good black ark!

From what I have read, there are a lot of different varieties of gold testing stone. One person I talked to even uses frosted black glass to do his testing. I did a little googling before I got my stone and I think there is a good chance that the Lydian stones (also known as Lydite) are black novaculite like black Arks. Here is an excerpt I bookmarked regarding that:

At the Silurian/Devonian boundary black cherts (locally called lydites or flinty slates) developed from radiolarians mainly in the Frankenwald region and in the Vogtland in Germany.

Of great importance are the novaculites from Arkansas, Oklahoma and Texas which were deposited at the close of the Devonian. The novaculites are milky-white, thinly-bedded cherts of great hardness; they underwent a low-grade metamorphism during the Ouachita orogeny. Their mineralogy consists of microquartz with a grain-size of 5 to 35 µ. The microquartz is derived from the sclerae of sponges and the tests of radiolarians.

During the Mississippian black lydites were sedimented in the Rhenish Massif in Germany.[7] The Lower Permian of Sicily hosts radiolarites in limestone olistoliths,[8] at the same period radiolarites have been reported from northwestern Turkey (Karakaya complex of the Pontides).

Got around to lapping my stone today and I can definitely confirm that the one from the Amazon link at least is either a black Ark or darn near the same exact thing. Laps slowly and cuts just like my black translucent Arkie.

I appreciate the good news!
I look forward to a lot of grit on a marble tile and some fur off the top of a DMT220 and upward!
~Richard

How do you guys Lap your ark? I'm having a hell of a time

Originally Posted by nicknbleeding

How do you guys Lap your ark? I'm having a hell of a time

Join the crowd!! Easiest is Silicon Carbide grains on a flat sheet of marble with a little oil. Barring that a silicon carbide wet dry paper on the marble tile. Apply a lot of time and effort. Take breaks often! I am still working down a translucent that had a 1/8th" deep wood carver's dish in it. The Translucent Arkies may be used as slurry raising stone for that reason; super fine grit tenaciously retained.
Worth the effort even if the hone is slow cutting to a final finish.
~Richard
~Richard

I, like Richard, use silicon carbide loose grit, but I use a cast iron toolmaker's lapping plate. Anything flat will work, it's just a question of how fast your reference surface will wear. It's important to spread the grit around and try to work whatever you're lapping over the entire surface regardless.

If I had to lap an 1/8" off an Ark, I would be using a diamond grit cup wheel on a grinder to rough it in first. Otherwise you're looking at days of work easily.

Originally Posted by eKretz

I, like Richard, use silicon carbide loose grit, but I use a cast iron toolmaker's lapping plate. Anything flat will work, it's just a question of how fast your reference surface will wear. It's important to spread the grit around and try to work whatever you're lapping over the entire surface regardless.
If I had to lap an 1/8" off an Ark, I would be using a diamond grit cup wheel on a grinder to rough it in first. Otherwise your looking at days of work easily.

Actually I did do a good bit with a Blue 80 grit on a cheap 4inch belt sander (Outside for sure and filter mask on! Not very flat but down to lappable! Not applicable here for the little stone.
~Richard

I have never heard of silicon carbide grains. Where do you get them and how do you use it?

ebay is a fair place for silicon carbide grits.