Broken cane?

[Robwell]

I have several marbles with this seemingly broke off piece of wood. Almost looks like a broken toothpick. Logic says cane but what is a Putney rod? Also without calipers is this best why to measure as close as you can?

[Steph]

Not from a cane. Not from a punty.

Machine-made marble with damage.  The white could be furnace brick.  That could have weakened the marble and made it more prone to fracture.

[Robwell]

OK I didn't see that coming. Thanks!

[wvrons]

Any wood would burn up at 2000 degrees at which this marble was made. You can get plastic calipers for $3.00-$5.00 . Some of the factories used box end wrenches to check size. It had to be steel because the marble was 800-1000 degrees. Calipers are the most accurate and plastic will not harm the glass. A draftsman circle template is close. Any office supply will have them for $2.00-$3.00 . You can find either on ebay. 

[Robwell]

Wow I didn't know you could get them so cheap! Oh yeah that's real hot come to think about it. I have some with same condition that are not glass to try to explain my ignorance. Think I may have a bad pic but you can still see. Got these with some clays don't believe they are glass. So ? Doesn't matter it's damaged really huh? Thank you!