TUSCANY is the heartland of Italy, and the blood of Tuscany is its wine. The mysterious Etruscans, whose civilisation vanished after they were conquered by the Romans, were making wine in Tuscany 3,000 years ago. Today, the three great red wines of Tuscany are Chianti Classico, Vino Nobilo di Montepulciano and Brunello di Motalcino. All are made principally from the native Tuscan Sangiovese grape or one of its clones. It was the ambition of Italian businessman Lionello Marchesi to own vineyards in the three areas. Already owning Val di Suga in Montalcino and Trerose in Monte Pulcino, he finally bought San Leonino at Castellina in the Chianti Classico area. This week's wine comes from that vineyard. It is full of dark, complex flavours and has a textured richness not easily forgotten. Area: Chianti Classico. Estate: Fattoria San Leonino. Grape: Principally Sangiovese. Importer: Valdivia. Price: $143 per bottle (case price). Availability: From the importer, phone 555-7431. Buying advice: An impressive Chianti Classico. Well worth the price.