quartzite

["John Vancamp" <jvcstnwrks@zzzzzzzzzzzzz>]

Not surprising as all of those stones are metamorphic counterparts to
common sedimentary stones.  A depositional sequence, particularily near
shore will have sandstone of different courseness, shales and silts (mud
deposits), quite possible conglomerates, and then limestone.  Metamorphism
occures when heat and/or pressure is added into the mix--usually because of
orogenic (mountain building) processes, which explains why metamorphic rock
is most often found in mountainous regions, and are often quite distorted
by folding and faulting.   In general terms, Quartzite is what sandstone
becomes.  Thus it is mostly composed of silicate (quartz) grains. Its
texture, grainsize, etc are functions of the nature of the sandstone it
evolved from.  Shale and silt turn into slate and shist type stone.  The
basic difference between sandstone, and shale is grain size --mud is only
real fine sand for the most part. Gneiss  is a strange bird as it can have
several different origins.  Basically it is metamorphic granite, but it can
also result from the metamorphism of course granitic sand (arkose), or the
intrusion of igneous rock into shist, or quartzite.  Many of the mercantile
granites sold for counter top material are actually gneiss.

Marble as we all know is altered/metamorphic limestone, although again,
many mercantile marbles are merely crystalline, or highly compacted
limestone that can be polished.

This is all very simplistic, and a deeper discussion would involve a lot of
upper level petrology, geochemistry, and geomorphology background
In short though,  it's all stone!!

JVC