A gemologist studies gems.
a person that studies gems is called a gemologist.
The correct title for someone who studies volcanoes and volcanic activity is vulcanologist, also spelled volcanologist.
I'm not sure about expert (most likely just called a professor) but somebody who studies gems is a gemmologist. A mineralogist is linked
A vulcanologist
Astro-physicist or simply astronomer would probably be the most accurate title.
a person that studies gems is called a gemologist.
The name of the map
A criminologist studies crime and punishment matters.
The correct title for someone who studies volcanoes and volcanic activity is vulcanologist, also spelled volcanologist.
I'm not sure about expert (most likely just called a professor) but somebody who studies gems is a gemmologist. A mineralogist is linked
A geologist studies rocks, minerals, and physical structure of a particular area. A gemologist studies gems and gemstones.
Ornithologist
Social Studies in Web 2.0
The noun criminologist is a singular, common noun, a word for someone who studies crime and criminals; the noun criminologist is a profession or a title for someone in that profession.
A volcanologist is someone who studies volcanoes. With the title, that person would be a geologist, and also the activity and formation of volcanoes, as well as current and historic eruptions.
The name for a gem expert is a gemologist. They are experts in natural and artificial gems.
Someone who studies evolution is called Evolutionary Biologist.