Alexandria gazette. [volume] (Alexandria, D.C.) 1834-1974, 1922-03-06
USEFUL \ MINERAL,

Washington, D, CA remarkable
variety OF uses for one OF the most
widely distributed constituents Of the
earths crust, silica, is named by. the
United States Bureau of Mines as the
result of a sSNiT fof the possibilities
of this, material. silica in its variolSs
forms, as quaatz, dnartzite, sahostonS
flint, .::tripoli,,' Raiatomaceoass earth,
sand and gravel, 5etc., findsisits way,
into the construction of the houses: in
which: We live, INTO the tooth paste
which most OF ussQse dailYhFnto the
photograph records which sTegale US
with canned music" andsinto the
thousand-and-one glass produets.
SILICON, dioxide occurs in atfree state
chiefly sduartz':s but hydfous silica
occurs Jas siopal, flint, dia&omacecus
earth, tripoli and;E so on. fQuartz IS
found in many FORMS ths,most i'm
tportant of>which are AS vein quartz,
|quartzite, sandstone, silica sand and
gravel; iast' crystals or crystalline
grains, masses or aggregates in. igne-
Gus rocks, such as grantees, dioiites
and pegnatites. SIS
F Free siTiea in it's varied forms is
very widelySdistributed, but deposits
Iof commsrcialsvalue are fars,fess conf
mon. HYWever, with the exception Of
such relatively scarce materials as
tripoli and flint grinding pebbles, most
forms of silica are sold fotE such low
prices that economic factoEs,, such as
proximity to railroads and ito local
markets, govern the value Ola deposit.
Thus deposits Of glass sand may be
valueles if located far from supplies
Of cheap fuel and far from large cen.
tiers of consumption Tor glass. IS
Methods of mining the various sill
ceous materials vary widely, depend
ent on the form of the material, nature
and location of deposits, and type Of
product to be made the Bureau OF
Mines found. Most OF the deposits
are worked by open-pit or quarrying
methods, often in a very crude way.
Sand deposits may be worked by n.y.
draulicklng, by dredging or by the use
of steam shovel. Vein quartz is
often obtained as a by-product in the
mining of other materials Pegamite
quartz is almost always obtained as d
by product in working pegamitc dikcs
for feldspar or mica.
Various forms of silica, in finely
ground state, enter into the compost.
ton of securing and polishing soaps
and powders, tooth-powders and paste.
Quartz, quartzite, sandstone and SAND,
coarsely ground and closely sized, are
used in the manufacture Of sandpaper.
The same material, crushed into sharp
grains, uniform in size, are used in
sand-blast work. For saving and pol
ishing marble and granite, sharp,
clean sand graded into various sizes
is used. Massive sandstone, very fine
to moderately coarse grained, is used
for whetstones, grindstones, pulp
stones and oil stones. ebert, flint and
quartZite in dense, solid blocks, are
used for subc-mill lining. Rounded
flint pebbles arc extensively employed
in tube mill grinding.
In making silica friedrich and other
retractories. fairly pure quartz,
known as gannister, is used. In max
ing silicon, ferro-silicon and silicon al
Toys OF other metals, such as copper,
moderately pure sand and massive
crystalline quartz are employed. Mas |
slve quartz and quartzite are used as
tiux in smelling basic ores. Fine
sand and ground tripoli enter into the
composition OF foundry parting sand.
In the various important chemical
industries, massive quartz or quartz
lite are used as Innings for acid towers.
Various forms of silica are used as
hltering mediums, and pure quartz
sand is used in the manufacture of
sodium silicate and carborundum.
Paint manufacturers employ finely |
ground silica of various varieties as
an inert extender. Finely ground
silica of all types is used as a wood |
filler and as filler in rubber, pressed
and nodded goods and in photograph
records.
In the pottery industry, flint, ebert,
and other forms Of silica, finely |
ground, are used as ingredients OF