~~~ question was asked a couple months ago that also included an image of an Ivory chip.

The response was: "How can you tell so fast?"

Then I explained what to look for.

This time I tried a "walk-through exercise" in explaining what to look for and how to do it in a difficult situation such as with the images Jim used... so others who are not sure what an Ivory chip looks like would try to study the chip in a manner where they will see the cross-hatching and nerve hole area in the center.

There are websites such as Hanover's and Eisenstadt's and Seymour's and Herz' books which walk the student through everything they need to know in reading a chip.