Erotic writing has nothing to do with this.
Italian villages can be red, because of red bricks and shingles, or grey, like stones.
In many villages in the countryside of northern Tuscany, Liguria and Emilia-Romagna roofs are covered of piagne or ciappe, flat, grey, stones
Walls, houses, churches, roads are made of stones…
This is Matera, in Basilicata
houses there are called Sassi, ‘stones’
and here’s Alberobello (Puglia) and the Trulli
50 shades of grey Italian style