A rock collector is an individual who has an interest in gathering and studying different types of rocks and minerals. There are several synonyms for the term 'rock collector', such as geologist, mineralogist, petrologist, lapidarist, and lithologist. Geologists study the Earth's structure, rocks, and minerals, while petrologists specifically focus on the origin and composition of rocks. Mineralogists are experts in identifying minerals and their properties, whereas lithologists study the physical and chemical properties of rocks. Finally, a lapidarist is someone who works with gemstones and cuts and polishes them to create jewelry and decorative pieces. Each of these synonyms has a unique focus and expertise within the field of rock collecting and earth sciences.