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QUARTZITE A compact granular rock composed of quartz crystals, usually so firmly cemented as to make the mass homogenous. The stone is generally quarried in stratified layers, the surfaces of which are unusually smooth. Its crushing and tensile strengths are extremely high; the colour range is wide GROUP Metamorphic
COMMON ROCK-FORMING MINERAL GROUP Siliceous
COMPOSITION Quartz being the most abundant mineral with a variety of other minerals. Its the metamorphic minerals that give this stone its distinct colors and appearance.
HARDNESS Medium to Hard
MOHS' SCALE 4 - 7 POROSITY 0.4 - 3.9 % ABSORPTION 0.1 - 1.4 % WEATHERING CHARACTERISTICS Excellent TENDENCIES Absorbs oils COLORS A wide variety of colors from very light white to silver...medium to dark grays...light to dark gold's...soft greens to olive green...blues, etc NOTATIONS If this stone is used where oils from foods will be present, it is recommended that the stone be treated with a oil repellent. **Geologically quartzite can be part of a continuous series of stones that grade into another type of stone.The divisional boundaries can involve hundreds of feet and are not clearly distinguishable and therefore become purely arbitrary. Quartzite can grade into a Mica Schist and if a quarry is in such a transitional zone this stone commercially may be represented and sold as a quartzite. Its appearance (texture/color) may be similar to a true quartzite, however, there will be a mineralogical deference and herein is were the weathering characteristics between these two stones defers. This transitional stone, in a wet/humid climate undergoes a mineralogical transformation that is progressive resulting in an overall color change to a dusty whitish color which is irreversible. This type of stone may also develop rust spots or whole tiles may change to a reddish rusty appearance.
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