Board Thread:Naruto Discussions/@comment-45444155-20200608233611/@comment-1751565-20200611011239

My opinion based on every data collected hints that Gaara can infuse Magnet Release chakra into his Sand...hence the Sand in his Gourd being more powerful than ordinary sand, hence the levels of density of the Sand changes ever so often...Gaara inherited Magnet Release via Rasa and was probably why he could best contain Shukaku as Jinchuriki...

Shukaku's Magnet Release is thru the use of its Curse Marks...hence why when Gaara used the Shukaku Shield etc curse mark pattern appear on the Higher density defenses...

After the War, and after his fight with his father, Gaara probably decided rather than just infusing Sand with Magnet Style chakra (similar to how Deidara infuses Explosion Style chakra into Earth Clay), Gaara started using His own "Inherited Metal Sand" and infused it with his Sand as well.

So in a sense yes Sand is Magnetic, but only if infused with Magnet Style Chakra, which Gaara and Shukaku accomplishes in their own ways.

Based on the anime, Sand ninja employs Sand Jutsu thru either Earth or Wind natures...so most likely it is just an advanced form of those elements, similar to how the 3 Tails has an advanced form of Water in the form of Coral. This would further make sense since we all know SHukaku utilises Wind Release primarily.

Shukaku and its Jinchurikis basically Manipulate Sand using the basis of Magnetism but does not Magnetise the Sand itself unless thru Shukaku's Curse Mark patterning or Gaara's Inherited Magnet Style from his Father (evidenced by the Black Eye Rings).