Ключевые слова: aggregates, assortment, calcite, closeup, collection, color, composition, compounds, crystals, earth, education, elements, formation, gemstones, geological, geology, hardness, igneous, layers, luster, macro, material, metamorphic, mineralogy, minerals, mining, natural, quartz, research, rocks, science, sedimentary, silicates, specimens, structure, study, texture, variety,