In the mineral beryl [beal ²(sio ³) 6], what is the ratio of beryllium to silicate (sio ³)?

Approximately fifty beryllium minerals occur in nature and over half of these minerals are silicates. Beryllium is mined primarily from these silicates, including beryl, Al 2 Be 3 Si 6 O 18 , 5 percent (wt.) beryllium, and bertrandite, Be 4 (OH) 2 Si 2 O 7 , 15 percent (wt.) beryllium. The world resources of beryllium are estimated at approximately 80,000 tons. Other common beryllium silicates include chrysoberyl, BeAl 2 O 4 , and phenacite, Be 2 SiO 4 . Read more: http://www.chemistryexplained.com/Ar-Bo/Beryllium.html#ixzz4zw3ZC1cm

The answer to the question is d