Andy,
  How about
Hobbyist...one not interested in shells but uses them in crafts
Beginner...just starting out collecting and studying
Amateur...seriuos interest but not planning on much depth of knowledge
Paraprofessional...grear depth, or narrow focus, in a discussion would not
                know them from a professional
Professional...does it for a living

Charlie
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Charlie Sturm, Jr
Research Associate - Section of Invertebrate Zoology
                     Carnegie Museum of Natural History, Pittsburgh, PA
Assistant Professor - Family Medicine

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