Generate a realistic portrait of Sir George Steuart Mackenzie, a 7th Baronet of Coul, in 18th-century Scottish attire, sitting in a study with geological and chemical equipment, books, and papers surrounding him, reflecting his occupations as a geologist, chemist, and writer, with a subtle background hinting at his Scottish heritage and connection to Iceland, in a formal and dignified style reminiscent of 19th-century British portraiture.