Ok guys. After some more research it seems that the rusted spots on the cross are actually a skull and crossbones and a note. The black is ebony wood. It seems to be mid 1800s
hard to say exactly when it was made. I've seen a site that says 'late 1800's - i.e. 1890's'. I've seen another site that says 'WW1 era', and another site that says 'early 1920's'. With that, I would assume that it is roughly 100 years old.
What you have is a pectoral cross worn by priests and nuns. Not so much these days, but in the 19th and early to mid 20th century this type of crucifix was quite common. The inlaid wood is normally ebony. I vividly remember them on every nun and priest when I was a kid. I have two that were given to me by a very special nun in our family who entered the convent as a young girl in the 1890s and lived to age 99.