Exploring Liguria's stone heritage
January 6, 2010
Although the Liguria region of Italy is not as storied as the historic stoneworking centers of Verona and Carrara, the area is home to a wide variety of stone architecture as well as a number of innovative stone producers. This past November, the Italian Trade Commission showcased Liguria’s stone industry to a delegation of international architects, including professionals from the U.S., the Netherlands, France, Brazil and the U.K.
The program included tours of the slate district of Lavagna, where material is quarried for architectural applications as well as billiard tables and blackboards. (In fact, the word “blackboard” in Italian is Lavagna, while the word for slate is Ardesia.) Architects also had the opportunity to visit two different quarries for Rosso Levanto and Verde Levanto marble, along with an ultra-modern tile-processing plant. They also studied the historic stone architecture of the Liguria region.
The program began in Genoa, where efforts are underway to upgrade many areas within the city. The architects began with a meeting at the Genoa Urban Lab, an initiative of the city that involves design and urban planning professionals from Italy and abroad.
The goal of the Urban Lab is to improve the city’s overall infrastructure with improvements that respect Genoa’s different environments of the neighboring sea and mountains. This includes urban renewal of spaces that are inland from the port as well as improving Genoa’s connection to the rest of Italy and Europe through improved railways.
It is expected that as Genoa’s revitalization progresses, natural stone will play a role in the areas of new construction, such as mixed-use high-rise projects. Stone restoration will also be critical as the city’s palazzos - many of which are in disrepair - are upgraded for modern-day functions.
Also in Genoa, an introduction to Liguria’s stone resources could be found at the “BI” product exhibition - held in the city’s famed Palazzo Ducale. This event, which was organized by noted architect Francesco Lucchese, was a collaboration of stone suppliers and designers to create new uses for the region’s slate and marble products. The focus was to design “everyday” products in stone, such as furnishings and other household items.
The resulting exhibition included materials such as Rosso Levanto and White Carrara marble - as well as slate - being utilized for objects such as modern lamps, bookends, serving trays and other decorative items. One of the most intricate projects was an ornate lamp designed by Des Setsu and Shinobu Ito and fabricated by Technotiles S.p.A., a large-scale stone producer in the Liguria region. The stone pieces for the lamp, which was made from White Carrara marble, was formed using a waterjet. Moreover, a combination of Plexiglas and marble provides light diffusion, and Technotiles had to devise an adhesive formula that would work effectively with both materials.
Following the tour of the exhibition, stone industry leaders from the region gave a joint press conference with members of the Italian Trade Commission, and the architects also had a chance to meet with the various suppliers who were involved in the project.
The following articles offer a detailed look at the program.
The palazzos and churches of LiguriaCentered in Genoa and radiating out to the countryside, the Liguria region features a notable range of classic architecture, and much of it includes natural stone as a signature element. As part of their education on Liguria’s stone materials, the architects were given a tour of many palazzos and churches within Genoa as well as outside the city.
The tour opened up at the Palazzo Ducale (Palace of the Doges) in Genoa, the first parts of which were built between 1251 and 1275.
The building is among the first examples of neoclassical work in Italy, and it features a range of materials from the Liguria region, including Rosso Levano and Rosso Verde marble. Stone materials were also brought in from the Tuscany region as well as Siena. Meanwhile, the columns at the building’s main entrance and courtyard are comprised of White Carrara marble. Much of the stone used for the building was transported to Genoa via the sea.
The palace was ultimately completed in 1539, and it was most recently restored over the course of an 11-year-long project that concluded in 1992, which marked the 500-year anniversary of city native Christopher Columbus’ voyage to America.
The building is now a government-owned facility and the site of political conferences. It also hosts a range of cultural initiatives for the people of Genoa.
San Lorenzo Cathedral
Originally founded in the fifth or sixth century AD, the building that now houses the San Lorenzo Cathedral in Genoa was started in 1307 and continued in various forms until the end of the 17th century. It was designed in a French Gothic style, and it features alternating horizontal bands of dark and light stonework - an element that is common among many notable structures in the Liguria region.
Again, local stone was used for much of the design, and some of the most intricate stonework can be found at the entryways. Ornate elements such as carved columns and detailing are combined with inlaid stone mosaics across much of the entrance, giving the cathedral a majestic presence whether viewed close up or from a distance. The cathedral is considered to be one of the top attractions in the city of Genoa, and the adjacent piazza is a popular gathering space for local residents.
Basilica dei Fieschi
About 40 minutes outside of the city of Genoa lies the Lavagna slate district, and while much of the region is rural in nature, classic styles of architecture can still be found - particularly among its churches. One example of this is the Basilica di San Salvatore dei Fieschi - more commonly known simply as the Basilica dei Fieschi - located in the city of Cognorno.
The original basilica goes back to the “Fieschi” village’s foundation in the middle of the 13th century, although reconstructions continued for several centuries. The exterior architecture mirrors that of many churches and cathedrals in Genoa, with alternating light and dark horizontal bands as well as a prominent rose window frame above the entrance. Unlike its counterparts in Genoa, however, the Basilica dei Fieschi features slate as a predominant building element - inside and out. The stone was taken from nearby Monte San Giacomo and the Fontanabuona Valley, which has evidence of 200 ancient quarry sites.
The exterior also utilizes White Carrara marble, which was used for cladding as well as some of the columns.
The Basilica dei Fieschi remains a centerpiece of the region’s culture, and its courtyard is the site of an annual neo-medieval event known as the “Torta dei Fieschi,” which takes place every August 14. The celebration is a recreation of the festivities that surrounded the wedding of Count Opizo Fieschi, older brother of Sinibaldo Fieschi, who would become Pope Innocent IV and initiate the building of the basilica in 1245.
Processing slate since 1925The Lavagna slate region features a range of producers - including long-tenured craftsmen as well as plants equipped with the most modern technology. Among the first exporters of Italian slate on a broad scale, Ardesia Biggio srl has been in operation since 1925.
The company has a long tradition of slate extraction and finishing, and it remains a specialist in creating slate for a range of billiard tables. It also has distinguished itself as a producer of slate slabs in a range of surface finishes.
Like most slate producers in the Lavagna region, Ardesia Biggio’s quarries are located underground, and one site is located adjacent to its main processing plant. The coloration of the company’s slate tends towards pure black, with a slight hint of gray, and the goal is to process slate that is as consistent as possible.
Given the level of precision needed for producing billiard slate, the slabs processed at Ardesia Biggio have an optimal level of quality. But in addition to having well-calibrated machinery, the company relies on experienced workers to split the blocks into slabs along the natural cleave of the material. It generally takes between five and 15 minutes to split a slab from the block, and the first split is always at the center.
After splitting the stone by hand, slabs have a natural-cleft finish. If desired, honing is generally done by hand using radial arm polishers. The company also has automated calibrating machinery from Bisso of Italy.
Before shipping, slabs are packaged in plastic and wooden frames as needed. In addition to slab production, Ardesia operates a second factory for slate roofing, paving and architectural elements.
An innovator in slate productionLocated in the Fontanabuona Valley, Ardesia Mangini Angela & Donatella snc produces first-quality Italian slate, and it reports that it has been exploiting its own quarries for generations. It processes a broad range of products, including slabs, paving, cladding, countertops, architectural pieces, roofing and other elements. Lately, it has also been developing some new finishes and textures, such as “Black Gold,” which includes gold leaf as part of the finished product; and “Black Crocodile,” which has a uniquely detailed surface that resembles the skin of a crocodile.
Slate is extracted from an underground mine, and during tile processing, the blocks are first cut into cubes and small, squared blocks on a Bisso bridge saw. From there, the squared blocks are split into tiles by hand by experienced stoneworkers, who must find the natural seam of the stone by eye before splitting.
The plant also has an automated processing line from Sasso Meccanica of Italy for slabs and other large pieces.
The company processes approximately 32,000 square feet of material per month, about half of which is exported.
Ardesia Mangini has supplied finished slate products for a range of notable architectural projects around the world, including the Barvikha Hotel & Spa in Moscow, Russia; a new showroom for Mobles Bellmunt S.L. in Barcelona, Spain; a new administrative complex for Dexia Bank in Luxembourg, and a new showroom for the Yacht Fair in Genoa, among others.
Working slate with advanced technologyArdesia Cueno Angiolino & C. made a name for itself in the slate sector for being one of the first companies to use modern equipment for slate extraction and processing. The strategy to be on the cutting edge of technology has stayed with the company over the years, and it utilizes a broad range of advanced machinery from Italy in its operation.
The company has been in the marketplace for more than 40 years, and its current factory, which is situated inland from Lavagna is more than 85,000 square feet in size.
When processing slabs, the company has automated honing lines from Terzago and Breton, and it also has an automated sandblasting machine to offer a variety of finishes.
Meanwhile, tiles are produced on an automated line from Socomac.
Some of Ardesia Cueno’s most impressive equipment is used for custom architectural products in slate and other stone materials. An Omag Mill 98 CNC stoneworking center offers automated processing for elements such as kitchen countertops, inlaid tables, vanity tops, fireplaces and architectural carving. Additionally, a waterjet is used for intricate cutting of slate and other materials, and it has produced inlaid medallions combining a variety of stones. Automated edge processing is completed using an Omega 60 edger from Comandulli, which can process materials ranging from 20 to 60 mm thick.
Additional Photos from Working slate with advanced technology
Operating an historic quarry siteApproaching Ditta Esmar srl’s current site for Rosso Levano marble in Bonassola (La Spezia Province), there is evidence of several quarries that were established during the Roman Period. And the company’s owners proudly point out these areas as evidence of the material’s importance over the years.
“It is one of the traditional stones of Italy, and it was a material for kings,” explained Catarina Rezzano of Ditta Esmar, who operates the company along with her husband. Vitorio. “It is now a family passion for us.”
The quarry site is located high atop the hills overlooking the Ligurian Sea, and while it also contains Rosso Verde marble, this material is only quarried on request. “Rosso Levanto is the prized material,” explained Catarina Rezzano. “It is considered to be a decorative stone, used for columns, statues, door frames and other details. It was used this way for the Tate Gallery in the U.K. [for example], and it is also exported to places like the U.S. and Saudi Arabia.”
A diamond wire saw from Pellegrini is a key piece of equipment during stone extraction, and blocks are completely squared. Heavy equipment such as a Caterpillar 215 backhoe is also used to clear waste and maneuver materials. Meanwhile, blocks are lifted from the quarry using a derrick crane.
“This is not a high-production quarry,” Rezzano said. “It is a craft to find the right material. You cannot really test, because even when you do core drilling and find some nice material, it may just be a ‘bubble’ and not a large section. You need experience and luck to find a good area of quarrying. Fortunately, we are in a nice section of the quarry right now.”
As quarrying operations progress, the land that was exploited is refilled, and the company has filled in up to 45 feet of bed material at a time. Additionally, waste stone is transported from the quarry to help fortify seawalls in the area.
Seeking pure Rosso LevantoAt Levante Marmi srl’s site for Rosso Levanto marble in Deiva Marina (La Spezia Province), the company is committed to finding the purest material possible. Its current location in the quarry is yielding blocks with a consistent red color, and it can continue quarrying 130 feet deeper from its present position - giving Levante Marmi confidence that it will be extracting high-quality material well into the future.
The company extracts blocks that can produce large slabs, and it is able to quarry large quantities of marble. The stone is primarily used for interior work, and Levante Marmi’s products have also been used for decorative items such as columns. Its material is also being used in a 1-cm format for the interiors of luxury yachts.
In extracting the material, the chainsaw is first used to make a horizontal cut at the bottom of the quarry face, and then larger cuts are made using a diamond wire saw. After the quality of the block is confirmed, all sides are squared with the diamond wire saw. Pneumatic drills are also part of the process, as they are used for splitting and for creating pilot holes for the diamond wire.
Several large-scale pieces of machinery are also at work in the quarry, including a backhoe for clearing waste material and a front loader for removing blocks from the quarry.
Waste stone is used for a variety of applications, including “river-washed” stones for landscape designs. It also maintains a retail operation with small stone handicrafts.
Making a science of stone productionThe tile production plant at Technotiles S.p.A. of Vezzano Ligure (La Spezia Province) is immediately striking for its level of automation and efficiency. But upon closer inspection, the facility houses a range of equipment not typically found in a stone production plant, such as an automatic unit to electronically classify finished tiles based on algorithms.
A division of Technostone, the company was originally established as a traditional stone supplier, providing material for architectural projects around the world, such as the Italian Embassy in Washington, DC. “For the past three or four years, I really wanted to be different and be at the forefront, pushing design itself,” explained company founder Dante Venturini. The marble tile production is marketed under the “Luce di Carrara” brand, and it is entirely comprised of White Carrara marble varieties, which are quarried near the factory.
Venturini explained that the factory - and the brand - were built on the principles of standardization, logistics and consistency. “Stone tiles take longer to realize their true color than ceramic tiles, due to the fact that there is so much water used in the production,” he explained, adding that this was the motivation to invest in a large-scale drying line that completely dries each tile so its color can be properly classified directly on the production line. “We work with eight varieties of White Carrara marble, each with its own pattern and tone, and we ensure each is perfectly consistent within that range.”
The factory for classifying and packaging tiles is equipped with the latest generation of technology from Barbieri & Tarozzi, and human intervention is practically unnecessary during the process. After the tiles within various categories are dried, they move along the line to a Flawmaster system from Surface Inspection of Bristol, England. This automatic inspection system was developed for the ceramic tile industry to classify tiles according to their quality, tonality and shade. The Flawmaster works with a wide set of algorithms to identify all types of mechanical and decoration defects. Giving an added level of quality control, designated specialists also review each tile before it moves on to the packing unit.
Tile are stacked and packaged automatically, and robotic forklifts are used to transport pallets of material around the plant. The tiles are packaged in distinctive “Luce di Carrara” boxes, and each is marked with all the relevant information for the material.
In addition to striving for perfect tile production, Technotiles has also partnered with prominent architects on a variety of initiatives. The latest of these is a collaboration with Foster + Partners where certain stone materials are grouped with complementary elements of glass, mirrors and other design elements in sample kits to offer inspiration to designers and homeowners. “We aren’t endorsing a particular stone, but rather we want to inspire the end user with different systems and concepts,” Venturini explained. “You start with stone and other materials, and the added value is the design. We seek to do this every year, and our last collaboration was with Francesco Lucchese for backlit onyx.”
Another initiative by the company is “Luce Diffusa,” which combines translucent onyx or marble panels with Plexiglas. The product is then hung on an innovative rail system that allows the material to be backlit without showing any support behind the stone.
“It was not easy to develop,” Venturini said. “We had to formulate the proper glue that would work with the stone and with the Plexiglas, and maintain a holding capacity of 5 kilograms per square centimeter. We also determined that we needed the stone to be at least 1 cm thick, or you would lose the depth of the stone.”