The geology of the Baratti and Populonia Park is dominated by formations of sandstone and tufa ("panchina"). The vegetation is generally fairly homogenous being predominantly typical Mediterranean woodland. Here and there however, it does preserve evidence of the flora which flourished in past eras when the climate was different from that of today.
In the Park there are outcrops of essentially two types of sedimentary rocks - sandstone and tufa - formed respectively 30 million and 150,000 years ago. Both are typical of marine environments. The sandstone was deposited in deep sea areas relatively far from the coast, whereas tufa is a coastal sediment deposited typically in shallower waters.
Sandstone, being more resistant to high temperatures, was used to construct smelting furnaces. Given the ease with which it could be extracted and processed, tufa or "panchina" was the material most used in construction work.
The Park vegetation is characterised by four main habitat:
- The rocky coast which has been colonised to within a few metres of the sea by fennel, wild carrot, helichrysum (everlasting), and by the silvery bushes of houseleek; whereas further towards the interior, juniper and the other evergreen shrubs characteristic of the Mediterranean shrub are to be found.
- The Mediterranean shrub (dominated by the ubiquitous evergreen oak) which is the vegetation most characteristic of the promontory.
- Mixed woodland which is made up of plant species which flourish in the cool humid valleys; these include chestnut, Spanish broom (which was used in charcoal burners), and the holly and laurel typical of mountain and Atlantic habitats.
- Uncultivated open spaces which have been colonised by the many herbaceous plant species like hawthorn, viper`s bugloss (blue thistle), great mullein, golden thistle, chicory, and garland chrysanthemum whose copious blooms in springtime colour the exposed slopes of the hills with splashes of pink, blue and yellow.
The great variety of plant species is also reflected in the fauna. Amongst mammals there are wild boar, porcupine, badger and fox. Typical among the birds are black cap, goldfinch, tit, magpie and buzzard. Finally, the reptiles include viper, ratsnake and tortoise.