Is Silestone the biggest quartz producer?

The question is Silestone the biggest quartz producer? is a relevant one. In fact many people discuss this topic. In truth to actually achieve the title of the biggest, we really need to breakdown all the information. Many engineered stone plants have several production lines, and some even have different engineered stone plant systems, so I've made a list based on my personal knowledge and all the available information.
I'm only going to evaluate the companies in the world that use Italian technology, as the Chinese brand has several plants in China which is difficult to give actual data about them.
Quartz Based Producer that use Italian technology:

• Silestone: they publicize that their the biggest in the world, I figure they should have 11 or 12 production lines installed

• Santa Margherita produces about 8.000 sqm every day, I assume it includes marble and quartz based material, as they have both plants operating in the same location.

• Compac, The Surface Company has a marble based plant in Spain and a Quartz plant in Portugal assumes it has a capacity of 2.5 million sqm per year;

• Quarella-Verona Italy, says it's the biggest agglomerate producer in the world with a yearly output of 4 million sqm, basically they have marble based plant and quartz based plant. Adding up the marble and the quartz capacity it's probably the biggest in the world, so they say. I have not mentioned Rover or Prestige, as I figure their productions are included in the numbers above.

• Caeserstone - Israel - Says to have a 2 million sqm yearly capacity, they are the oldest company in Quartz based agglomerate, they started their plant in 1987.

• Çimstone-Izmir Turkey, 2 lines, no quantity specified.

• Stone Italiana: no available information about production capacity, but one thing I can tell you, their the most expensive in the market, but also the ones who have cutting-edge products.

• Okite-Italy: no available information on production capacity

• Diresco-Belgium: capacity to produce 4.000 sqm per day

• Sidera - Romania: 100.000 sqm per year

• Technistone - Czech Republic: 2 production lines and are negotiating to double their production capacity

• Nexus-Germany: just re-started production ... 1 production line

• Plaza Stone -Russia

• TotemQuartz -Iran: 1.000 sqm per shift, needless to say that normal production lines work 3 shifts.

• Gulf Stone- Oman: no available information regarding production capacity;

• Zodiaq-USA: no available information

• Vicostone-Vietnam: They currently have 2 production lines, no available information regarding production capacity

• HanStone - South Korea: no online information available

• RomaStone - Taiwan: 98.000 sqm per month although they have a block producing plant and mainly deal in marble based material;

• RMC-Portugal: have a marble block plant and no available information on production capacity;

• Yunfu Breton Stone Building Materials - China: 1 block plant to produce marble based material output not available

• Pokarna - India: no available information regarding production output

So this is about it, hope I didn't miss any Breton Plant for engineered quartz or engineered marble (which use polyester resin as a bonding agent). The answer to the question of this post is: if you just take the engineered quartz part of the business then Silestone is the biggest in the world, but if you add the engineered marble and look at engineered stone or composite stone as some usually call it, then we have Quarella in the top position.