Red spinel is a durable gem with excellent brilliance, known for its pure red to slightly purplish hues, and is often mistaken for ruby. Historically, spinel and ruby were not distinguished, with notable examples like the Black Prince's Ruby actually being spinel. Spinel originates from alluvial deposits and is primarily mined in Burma, Sri Lanka, Tanzania, and Tajikistan, coming in various colors, with red being highly sought after.