I am taking a family trip to Puerto Rico in January. From there, I will hop on a cruise ship and travel the Caribbean for seven days. I just wanted to know what kind of rocks I should be looking for when I walk the beaches. Also, what are the guidelines to bringing back unpolished beach rocks on the airline?|||There are no rules to prevent you from bringing rocks in your checked baggage. You cannot bring soil or dirt as the Dept. of Agriculture will take it away from you if they discover it. Clean sand is okay. I don't recommend trying to bring rocks or sand in your carry-on baggage. The scanners cannot see through these materials and then they will search your luggage and probably you as well. I carry rock samples in my checked baggage regularly. On the north shore of Puerto Rico you will find quartz sand beaches, and mostly rocks will be quartz, limestone, marl, and claystone. You may find coral fragments. You may also find some ooids (small round grains of calcium carbonate) in the sand. On other parts of the island you may find igneous rocks, such as volcanic rocks like tuff, ash, or basalt, and you may find metamorphic rocks like amphibolite, gneiss, and serpintinite on the southwest part of the island. Here is a geologic map: http://cgsc.biology.yale.edu/prgeolog.html Be careful what you eat at those beachside food stands.

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