Background. Verde Spluga (also “Splügen-Quarzit” or “Pietra Smeralda”) is one of the classic Alpine dimension stones and has for decades been among the most widely used Italian green natural stones in Germany and central Europe — above all as external flooring, stairs, facade stone and high-grade dimension stone for architectural projects. The DNSA (German Natural Stone Archive) lists the selection as “Very frequently used in Germany”. The selection was traditionally also built into historic dimension-stone applications in the Swiss architectural region of Graubünden, at the Splügen Pass.
Geology and occurrence. Petrographically, Verde Spluga is a Permian gneiss — a highly metamorphic silicate rock recrystallised by pressure and heat during Alpine orogeny over tens of millions of years. Geological age: approximately 270–290 million years (Permian). Its mineral composition comprises quartz, plagioclase feldspar, muscovite (a silvery lustrous mica) and above all chlorite (the green, layered magnesium-iron silicate) — chlorite is what carries the characteristic green colouring. The deposit lies in the Isolato/Madesimo quarrying area at the Splügen Pass (Italian “Passo dello Spluga”), in the province of Sondrio in the Lombardy region of Italy, at around 1,700 m above sea level. In international stone trading, Verde Spluga is occasionally listed as a “quartzite” — that is a commercial classification, justified by its acid-proof mineral profile and its hard rock behaviour; petrographically, the correct designation is gneiss.
Appearance. The ground tone is a calm sage green to silvery emerald green with subtle warm or cool undertones depending on the incidence of light and on the batch. Fine wavy bedding structures (foliation lines) run across the surface — the typical characteristic of a metamorphic gneiss with foliation. Distributed across it are silvery lustrous muscovite and fine greenish chlorite flecks that give the slab a subtle pearly shimmer depending on the light. From a middle distance the surface reads as a calm green dimension-stone field with an Alpine effect; close up one discovers the fine crystalline mineral structure with its wavy foliated bedding lines. The unidirectional foliation can be taken into account in the layout at installation. The selection cannot be polished to a high gloss — inherent to the material, only a matt, silky sheen is achieved, which perfectly supports the calm Alpine dimension-stone character.
Technical properties (DNSA values #3751). Bulk density 2,675 kg/m³, compressive strength 193 MPa (almost identical after frost), flexural strength 18.5–19.3 MPa, water absorption 0.29 %, abrasion group 2.39 cm³/50 cm², Mohs hardness approximately 6–7. Verde Spluga therefore sits in the most stable range of the hard rock family and is statically and mechanically fully load-bearing for all demanding applications. Frost-resistant (DNSA-confirmed), de-icing-salt-resistant, fully UV-stable. Acid sensitivity: individual mineral constituents (in particular chlorite and calcite fractions in stylolite lines) are not permanently acid-resistant — the stone is therefore not to be regarded as a 100 % acid-proof hard rock for acid exposure in the kitchen, unlike pure granites or quartzites.
The ROSSITTIS range. The finishes currently available from stock are listed in the »Finishes« block further down this page. From the slabs we fabricate internal and external floors in large or tile formats, stairs with treads and risers, wall claddings, window sills, skirtings, external floor coverings, pool surrounds, terrace slabs, bar counters and facade elements. One particular strength: in its traditional application as a floor dimension stone in Alpine and sub-Alpine buildings, Verde Spluga has been proven for decades in German homes, public buildings and hotel lobbies.
Comparison. Within the family of green Alpine dimension stones, Verde Spluga positions itself as the calm, planar, classic choice with fine foliation. Related Alpine bedded rocks are Verde Tinos (Greek, with white-green veining), Verde Andeer (a Swiss gneiss from the Domleschg in Graubünden), Andeer granite (somewhat lighter grey), Vals quartzite (Swiss, with more dramatic bedding lines) and Brione gneiss (Ticino, darker grey-green). Compared with Pietra Serena (a Tuscan sandstone), Verde Spluga is markedly harder, more weather-resistant and more acid-proof as a dimension stone for loaded surfaces — Pietra Serena reads as finer and greyer, but is softer. Compared with true green marbles such as Verde Alpi (Aosta Valley), Verde Issorie or Verde Guatemala, Verde Spluga is markedly harder and better suited to external use, but with less dramatic veining. Compared with quartzites such as Verde Bahia (Brazil) or Esmeralda Quartzite, Verde Spluga is calmer in its mineral grain and has a characteristic foliation structure rather than a clastic texture.
A frank assessment. Verde Spluga is the ideal choice for any application calling for a calm, Alpine green dimension-stone effect together with full technical load-bearing capacity. The selection performs particularly strongly as external floor covering, stairs, pool surround, facade panel and internal flooring in sub-Alpine residential and commercial buildings. Anyone looking for powerful, dramatic veining should turn to true green marbles such as Verde Alpi or Verde Guatemala; anyone wanting a livelier, more strongly coloured green should switch to Verde Tinos or Verde Eucalyptus; anyone who needs a fully acid-proof hard rock for heavily used kitchen worktops should turn to classic granites or true quartzites.
