| − | '''Topaz''' is one of the hardest minerals rating an 8 on the [[Mohs Hardness Scale|Mohs hardness scale]]. Chemically, topaz is Aluminum silicate fluoride hydroxide Al<sub>2</sub>SiO<sub>4</sub>(F, OH)<sub>3</sub> and is classified as a [[silicate]]. It is commonly used as a gemstone and its crystals can grow to a very large size. Topaz is commonly a shade of yellow or orange, but may also be colorless and is found in the [[blue]] and [[green]] ranges. Topaz is the [[birthstone]] for [[November]]. | + | '''Topaz''' is one of the hardest minerals rating an 8 on the [[Mohs Hardness Scale|Mohs hardness scale]]. Chemically, topaz is Aluminum silicate fluoride hydroxide Al<sub>2</sub>SiO<sub>4</sub>(F, OH)<sub>3</sub> and is classified as a [[silicate]]. It is commonly used as a [[gemstone]] and its crystals can grow to a very large size. Topaz is commonly a shade of yellow or orange, but may also be colorless and is found in the [[blue]] and [[green]] ranges. Topaz is the [[birthstone]] for [[November]]. |