no, because rock is being eroded to form the sand all the time.

In each moment there is, but the moments are very short.

No, for several reasons.

New sand is being created all the time, as the waves in large bodies of water grind rocks againsts rocks, shells against one another or rocks, and 1break coral into bits. Wave also bash against rocky shorelines or cliffs, eventually fragmenting them into sand.

Also, active volcanos dump molten lava into the ocean, where it instantly shatters into sand. Moreover, glaciers grind boulders into pebbles, and grind those into sand.

The wind also creates sand, in part by blowing sand across rocks and thus sandblasting away the surface into additonal granules.
Sand is not uniform in size. Constantly, grains of sand get broken into smaller grains of sand.

Sand also arrives steadily from outer space, in the form of meterites that burn up in the atmosphere, with part of their residue becoming grains of sand. And there are endless micrometeroites that fall to the earth as sand particles.

Even humans create sand, for example as the residue of burning coal. The clinkers (ashes) are sometimes ground into sand for making construction blocks, and sometimes just be pulverized in the disposal process. Whenever stone is cut, fine sand is created in the "sawdust" of the cutting. Even our cars grind bits of sand away from the highways and roads, as we move.

So the creation of sand is a constant process, with new grains of sand emerging somewhere every nanosecond.

While all this is occurring, sand that got deposited at the bottom of the oceans mixes with mud, and eventually gets compressed into sandstone. But sandstone can be eroded or scraped, releasing its constituent grains of sand or perhaps making new grains of sand. It would be very difficult to determine when during this process individual grains of sand lose their identity as sand, and instead become part of a larger mass of stone.

Sand is also consumed as the motion of tectonic plates drags it under an adjacent plate, ultimately driving it back into the earth's molten core.

With these processes occurring constantly, over the entire world, there are billions of grains of sand being created every second. And correspondingly, vast amounts of sand disappearing every second.

Yes but you would need to choose a time frame in which a snap shot could be taken... It might mean choosing nano seconds in time though!

there is no definite number of grains of sand.
as mining works continue, as rocks continue to exfoliate, as we humans work daily and so on, particles of the sand you see tend to keep on disintegrating. ther's therefore no way one can count such. since sand is therefore uncountable, there's no point trying to measure. only God knows the number, as it is said in the bible, and since we're not God, no point at all trying to measure.

By way of comparison, consider the famous Indian legend about the invention of chess and the grains of rice. The inventor presents the game to the king and asks for payment in grains of rice – one for the first square, two for the second, four for the third, eight for the fourth, and so on. There are 64 squares. The result comes out at 1.84 × 1019 grains of rice, which is about 4,000 times less than the number of grains of sand in the world on the basis of our calculations above. To bring the number of grains of rice up to our number for the grains of sand, you would need a chessboard with 76 squares instead of 64.
The mass of the Earth is approximately 5.98×1024 kg.
If the question is taken literally – namely, how many grains of sand there are in the world – we are interested specifically in rock detritus with a particle diameter of 0.06-2 mm. According to standard sedimentological classification, detrital material is called clay if the diameter of the particles, d, is less than 0.002 mm, silt if d is 0.002-0.06 mm, sand if 0.06-2 mm, gravel if 2-64 mm, cobble if 64-256 mm, and boulder if greater than this.
If the diameter of the grains is on average 1 mm, this would give 1.30 × 109 (1,300 million) grains in one cubic metre of sand.
For the sake of argument, say that all the sand in the world forms an even layer, 10 cm thick, over the entire surface of the earth, which covers 510 million km2 (200 million square miles). Then the volume of the sand will be 5.10 × 1013 cubic metres and the number of grains thus
5.10 × 1013 × 1.30 × 109 = 6.63 × 1022
http://www.visindavefur.hi.is/svar.asp?id=4803