Labradorite (Opalescent feldspar).—On
the road to Charlotte, Mecklenburg County, and near Bakersville,
Mitchell County, specimens showing a slight blue chatoyancy are found.
This domestic labradorite is scarcely used at all in the arts, as the
mineral from Labrador is cheaper and of a much superior quality, and
takes a fine polish.
Leopardite.—This
is a rock composed largely of whitish feldspar (orthoclase and
plagioclase), spotted black, perhaps by manganese oxide, and named from
its leopard-like appearance. It is abundant near Charlotte, Mecklenburg
County, and also in Gaston County. It is not a definite mineral, but a
variety of porphyry with disseminated crystals of quartz, and occurs in
large masses as a rock, so that it would furnish a good ornamental
stone, if polished. This variety of spotted feldspar is peculiar to
North Carolina, and has been described in detail in the report on
Building Stones.
The
beryl, zircon, and other gem minerals, which are also constituents of
pegmatitic dikes, are described in the following chapters.
