I was little and the caves seemed huge, the mica glittered, and I remember huge transparent sheets of mica that I ... There are a number of types of mica, two of the most common are muscovite ...

The mica issue surrounds muscovite, one of the most common types of mica found in quarried ... the more susceptible it is to breakage. A total limit of 1 per cent impurities (including pyrite ...

Micas are types of minerals found in the ... Statutory Instrument number 288 of 1949 set a 1 per cent at total limit for impurities such as pyrite and mica in concrete blocks.