SPECTACULAR QUARTZ CRYSTAL WITH SIDERITE SHEET WITH A SPECK OF ARSENOPYRITE IN THE CENTRAL PART. WE CAN ALSO OBSERVE A QUARTZ CRYSTAL IN THE MIDDLE OF SIDERITE OF SURPRISING QUALITY. PIECE EXTRACTED IN PANASQUEIRA, PORTUGAL. PRIVATE COLLECTION PIECE
Quartz is the most common mineral, the most abundant that can be found on earth.
It is composed of silicon and oxygen with the formula SiO₂.
According to the Nickel-Strunz classification, quartz belongs to the class of oxides, while in the Dana classification, it is considered a tectosilicate.
There are multiple varieties of quartz, colors and types.
