This article reports that "producing a single iPhone (6) requires, roughly, mining 34 kilos of ore, 100 liters of water, and 20.5 grams of cyanide." Also, "a billion iPhones had been sold by 2016, which translates into roughly ...37 million tons of mined rock". https://www.vice.com/en_us/article/433wyq/everything-thats-i...

Those numbers are pretty substantial - we shouldn't underestimate the environmental impact of our smartphone and gadget addictions.