Heezlewurst's Elemental Buffer

What's it called? Heezlewurst's Elemental Buffer (in short, HEB).

What does it do? The main use of (uncle) Heb is to cast a protective magical shield around you that protects thee partially of the effects of adverse attacks of elemental magick. The nature of the protection is determined by the Rhokshial's crystals you employ in the cast: red protects against fire, blue against cold, green against acid and yellow against noxious fumes. Employing all of them should protect against all these and maybe, plasma attacks (from the Spear?).
I find the spell of little use, as I am very unusually the victim of magic attacks, and even in that case, the protection given by this spell is only partial (approximately, it soaks half of the damage). Its only real uses might be in pkdom, to avoid painful backfires, or as an extra protection while walking around the Alchemist Guild, but even then, I fear it would be too cumbersome to remember and have the components for any good it does.

Where is it? It rests, generally undisturbed, in the Introeductyon too thee Strukture of thee Multyverss grimoire, at the Unseen University Library.

What does it require? The focus of an octogram and from one to 4 different Rhokshial's crystals, at will. The crystal(s) being consumed in the casting.

What skills do I need? Channeling, Evoking, Binding, Enchanting, Convoking

Has it worked? A correct output should be something like this:

You prepare to cast Heezlewurst's Elemental Buffer on a a small blue crystal, a small yellow crystal and a small red crystal.
You look closely at a small blue crystal, a small yellow crystal and a small red crystal.
You feel how the octogram affects magic nearby.
You observe the symmetries of a small blue crystal, a small yellow crystal and a small red crystal and the octogram.
You stare deep into a small blue crystal, a small yellow crystal and a small red crystal.
You drop a small blue crystal, a small yellow crystal and a small red crystal into the centre of the octogram.
A small blue crystal, a small yellow crystal and a small red crystal seem to twist and merge into a hazy blue, yellow and red stream of light, which rises and surrounds you.

Notes:

The spell is damn huge. It occupies tons of mindspace, takes some time to cast and consumes an outstanding 300 gps.

Different outputs have been known to happen. As I don't cast this spell regularly, they might be even more abundant. I got this one once:

You prepare to cast Heezlewurst's Elemental Buffer on a a small blue crystal, a small yellow crystal and a small red crystal.
You examine a small blue crystal, a small yellow crystal and a small red crystal.
You sense the magical field of the octogram.
You count the faces of a small blue crystal, a small yellow crystal and a small red crystal and the points of the octogram.
You hold a small blue crystal, a small yellow crystal and a small red crystal tightly in a fist.
You hurl a small blue crystal, a small yellow crystal and a small red crystal into the centre of the octogram.
A small blue crystal, a small yellow crystal and a small red crystal seem to twist and merge into a hazy blue, yellow and red stream of light, which rises and surrounds you.

Help Information:

Heezlewurst's Elemental Buffer - Magical shield.

Heezlewurst's Elemental Buffer is a first order defensive spell that should be cast on Rhokshial's crystals of the appropriate nature in order to generate a shield against offensive manifestations of elemental magic.