Deep sand dunes as easy source of silicon

Silicon is nice as a building material since it is the most abundant element around on Earth.
(Ignoring oxygen that can't be used on it's own to build anything.)

Extraction effort

Since silicon is a non-volatile element
it can't be drawn from the atmosphere like the building material
carbon can be from atmospheric carbon dioxide (as done by trees).

Fine sand would obviously be an easy resource not requiring hard rock mining.

Destructiveness on life & geologic history records

Life

With some precautions on

• sterile operations
• water table preservation
• migration path preservation

eventually present microbial life deep down the dunes interior
may be quite resilient through it's homogeneous distribution and spread over a very large volume.
Actual investigations needed to confirm.

Geology

Drawing carbon from air is nondestructive as
atmospheres are structureless and thus in-destruct-able in the literal sense of the word.
(Well, ok, the CO2 gets destructured but hat is deletion of value devoid redundant trivial information.)

For silicon instead some sort of more or less geology destructive mining and transport is needed.

Sand, as the choice of source, is already a quite homogeneous substance.
Remnant geologic historic information only being present inside the grains.
Erosion has already erased much of the origin history.
And since sand is homogenized removing a part of it for chemical processing will
still leave the same amount of geology history information in the remaining rest of the sand.
A bit like holographic data storage a weak analogy.

Best silicon based gemstones

See also: Silicon

Most silicates are "merely" around Mohs hardness 7 often below.
Nothing near diamond lonsdaleite and even sapphire.
Quartz itself being the defining element of Mohs 7.
Crystal structures are often on the more nontrivial
complex side in unit cell size or low unit cell symmetry.

Polymorphs

There are very hard and unusually dense metastable high pressue modifications of pure SiO₂
like the tetragonal stishovite with rutile structure.

Binary compounds

More thermally stable and similarly hard there are the silicon nitrides including nierite.
Nitrogen, while much less abundant than silicon,
is obviously extremely available on Earth as the main component of our atmosphere.

Running out of atmospheric carbon dioxide to make moisanite
(as discussed on page: Large scale carbon sequestration in deep sand dunes)
there is still plenty of nitrogen to make nierite

A danger of depleting our atmosphere of nitrogen would, if anything, be a very long term prospect.
It would be very possible though due to silicon being much more abundant than nitrogen.
And bad. Not to mention the problem of all the released oxygen
if not bound to some reducing element like unoxidiced iron which is hard to come by
in these enormous quantities without reaching deep down into Earth.

Looking at just sand dunes are though these are a minute part of earths silicates.
=> Q: How much of sand dunes would be consumed when combined with all of Earths atmospheric nitrogen?

Related

• Large scale carbon sequestration in deep sand dunes - one possible use of silicon ins and dunes