The symbol you speak of, on the key chain from Israel, is a traditional sign
to ward off evil spirits. Most of us would think of this as too close to witchcraft
for our tastes, but it is generally included in Middle Eastern and Israeli tradition
as this anti-evil-spirit symbol. You can see ads for this type of design at
websites which sell Israeli jewelry, the eye with the blue stone.
In New Mexico, the "traditional" people paint doors blue for the same reason,
to ward off evil.