I’m not sure when or why these spells would be handy, or why sand was chosen. Perhaps as base components of a lab with an experimental specialisation. Or a Magus with a minor magical focus in sand, akin to a focus in bronze, stone, or ice – as sand is not quite as versatile as other focuses but still has many applications.
Remarkably Magnetic Sand
Muto Terram 10, R: Touch, D: Sun, T: Individual
The targeted sand is made magnetic, gathering together and allowing moulding into unusual shapes.
(Base 3 for slightly unnatural, +1 Touch, +2 Sun)
Remarkably Bright Sand
Muto Terram / Ignem 15, R: Touch, D: Sun, T: Individual
The targeted sand glows with an eerie luminescence, while noticeable it is not bright enough to replace a useful source of light.
(Base 4 for highly unnatural, +1 Touch, +2 Sun)
Transmutation Between Oil and Sand
Muto Terram / Aquam 10, R: Touch, D: Sun, T: Individual
The targeted sand is changed to oil, and oil to sand.
(Base 3, +1 Touch, +2 Sun)
All the 544+ new spells for Ars Magica can be found here.