Pencils may look alike, but they can be very different!
Here's how you can tell them apart:

Pencils made from Incense-cedarⁱ (a renewable resource) are a reddish brown inside with a smooth, fine grain and a visible seam. They also have that familiar cedar scent when sharpened!

The Story of Pencils Lesson Plan: Activity 2 - The History of the Pencil?

The Early Days
Modern pencils are the descendants of ancient writing instruments.