lead ***
pencil lead

Then he or she takes out a thin section of tissue (about the size of a pencil lead), rather than a few cells.

This was his first tattoo, created by himself as a teenager with a sewing needle and pencil lead.

The numbers emerged, white against the gray of the pencil lead, just above the words "Once upon a time."

Perhaps you can find recipes for pencil lead on the Internet.

The wall was covered with scrawls done with a bit of pencil lead.

It was the size of a pencil lead, and packed with dust.

In 1802, they patented the first pencil lead made from a combination of clay and graphite.

The familiar scent of pencil lead caught Jack's senses.

Each pupil was constricted to about the size of a pencil lead.

One morning Nell looked out the window and saw the world had turned the color of pencil lead.