The Gist
Sour cherry, iron/rust minerality, and a dried tomato-leaf or oregano note add up to Sangiovese — especially from Tuscany (Chianti Classico, Brunello). The iron comes from Tuscan soils and the grape's thin skins. No iron note, no tomato herb? Probably not Sangiovese.
Mechanism
The iron/rust character in Sangiovese comes from high ferric mineral content in Tuscan alberese and galestro soils, and Sangiovese's naturally thin skins and high acidity, which result in high phenolic grip. The tomato-herb and dried oregano notes are terpenic/phenolic compounds shared between the grape and the Mediterranean macchia.
Sour cherry + iron/rust + dried oregano/tomato paste = Sangiovese. The iron note is specifically Tuscan — Sangiovese from other regions rarely shows it as intensely. Chianti Classico and Brunello di Montalcino are the testable expressions.
Deeper mechanism
The confusion between Sangiovese and Tempranillo: both medium-garnet with dried herb, leather, and medium tannin. Separators: Sangiovese has iron/rust minerality and sour cherry; Tempranillo has American oak dill/coconut (Rioja) and dried cherry/strawberry without iron. Sangiovese is more acidic; Tempranillo is rounder.
Confusion analysis
Sangiovese vs. Nebbiolo
Iron is present in both but different: Sangiovese has iron/rust with sour cherry and tomato-herb. Nebbiolo has tar + dried rose — no tomato, no oregano.
Sangiovese vs. Tempranillo
Iron/rust + sour cherry + tomato herb = Sangiovese. Dill/coconut/vanilla oak + dried cherry + dusty earth = Tempranillo (Rioja). No overlap on the iron note or on the oak signature.
Related varietals
This concept comes up when tasting: Sangiovese