Heřmanov

Heřmanov is a small nature reserve lying just south of the village bearing the same name, in the Žďár nad Sázavou district of the Vysočina Region in the Czech Republic. The protected area covers a mere 1.9 hectares, occupying a small patch of woodland surrounded by farmland, right next to a road leading toward the village of Heřmanov. Despite its modest size, the site holds significant scientific value: it is one of the few places in the world where visitors can find the so-called Heřmanov spheres.

What are the Heřmanov spheres?

The Heřmanov spheres are a unique mineralogical formation that develops where a pegmatite vein meets bodies of serpentinite. They take the shape of lenses or spheres, typically at least 10 centimeters in diameter. Their core consists of dark brown, flaky aggregates of phlogopite, wrapped in a greyish-green, compact mass of clay minerals — mainly montmorillonite. The outer layer is made up of greyish-brown, needle-like aggregates of anthophyllite, a mineral from the amphibole group. This layered structure means that a broken sphere resembles a mineral "onion," a genuine rarity among geological finds in Central Europe.

Why was the site protected?

The area was formally declared a natural monument in 1990, specifically to protect this one-of-a-kind mineral deposit. The surrounding bedrock is made up of varied rocks of the Moldanubian group, dating to the Proterozoic era, and the spheres themselves formed in the contact zone between the pegmatite and desilicified serpentinites. Given the scientific importance of the find, the site requires ongoing protection — it remains vulnerable to unauthorized collecting by mineral hunters, one of the main threats to preserving the deposit intact.

What grows in the reserve?

The vegetation within the small woodland is largely self-seeded. Species typical of moist, field-edge groves dominate the area, including common alder, silver birch, and trembling aspen. The tree cover here is not the result of deliberate planting but of natural succession on a small strip of land left standing amid the surrounding farm fields.

Frequently asked questions

Where exactly is the Heřmanov natural monument located? It lies south of the village of Heřmanov, in the Žďár nad Sázavou district of the Vysočina Region, next to the road leading toward the village.

How large is the protected area? It covers approximately 1.9 hectares — a small patch of woodland surrounded by farmland.

What can visitors see here? The main attraction is the Heřmanov spheres, rare mineralogical formations made up of phlogopite, clay minerals, and anthophyllite, which form where pegmatite meets serpentinite.

When was the site placed under legal protection? It was designated a natural monument in 1990, specifically to preserve this unique mineral deposit.

Is it allowed to collect minerals here? No — the area is protected precisely because illegal collecting of the Heřmanov spheres by mineral enthusiasts poses a real threat to the site.