Question

6. Amphiboles display solid solution. Using the chemical formula of anthophyllite as a starting point, add and subtract components to make actinolite, tremolite and hornblende. Anthophyllite + = tremolite + = hornblende

Answer 1

Answer and Explanation:

Amphiboles are a group of minerals that display solid solution, meaning that their chemical composition can vary within certain limits. Anthophyllite is a magnesium iron silicate hydroxide with the chemical formula (Mg,Fe)7Si8O22(OH)2. Tremolite is a calcium magnesium silicate hydroxide with the chemical formula Ca2Mg5Si8O22(OH)2. Actinolite is a calcium magnesium iron silicate hydroxide with the chemical formula Ca2(Mg,Fe)5Si8O22(OH)2. Hornblende is a complex calcium sodium magnesium iron aluminum silicate hydroxide with a general formula of (Ca,Na)2-3(Mg,Fe,Al)5(Si,Al)8O22(OH)2.

To make tremolite from anthophyllite, one could subtract iron and add calcium. To make actinolite from anthophyllite, one could subtract some magnesium and add calcium and iron. To make hornblende from anthophyllite, one could subtract some magnesium and add calcium, sodium, aluminum, and possibly more iron.