Just to be impossibly original...

Similarities:

-worth

-material- copper

-"In God We Trust"

- Good ol' Abe

-imprint/ engraving

-shape

- importance-

-length/ width/ height

-notches on the edges

-use

- place of origin

-representation

-owner

-purpose

-name

-lifespan

-weight

-volume

-scent

-reflection

Differences:

-colour

-age/date

-travels/ experiences

-weathered/ worn down

-letter under date

- chips/ indents

- deeper imprints

-sheen

-green tinge

-cleanliness

-fate

-dirt engrained into metal

-heaviness

-stories

- hands they have passed through

- highlights

- scratches

-way of aging

- hair on Abe

-angle of the bow tie