Chrenedict's Calcareous Covering

What's it called? Chrenedict's Calcareous Covering (in brief, CCC)

What does it do? The more usually called 'trollskin' creates an outer, rocky and stone-like layer of skin that protects its user from pointy weapons getting to his 'voonerables'. As such, it acts as a perfect backup to other protective methods and spells (and usually, it is a wizard's third level of protection, after EFF and TPA, and perfect for the function of soaking some damage in the brief but unconfortable moments of running away when both the previous ones have been brought down -or TPA is weakened and lets some damage through). Blunt weapons don't suffer any penalty against it, but sharp and piercing ones will get damaged as if your adversaries were attacking a real troll.
As Spellcheck Project appropiately comments, its only setbacks are the inconvenience of the components, the difficulty of various successive castings, and the limited (skill-based) number of hits the skin will deactivate before peeling off, as well as its non-use against blunt and unarmed attacks (which add their hits to the deactivating count).

Where is it? To fetch it you will have to struggle with the rigid and granitic pages of Thee Dyscyplyne of thee Stoane grimoire, at the Unseen University Library.

What does it require? Three components to fetch: a ball of sap, a 'grade four varnish' (takes the form of a fish) and a handful of chalk powder. All are consumed in the process.

What skills do I need? Binding, Earth, Binding (2)

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

You prepare to cast Chrenedict's Calcareous Covering on xxx (yourself/target).
You rub sap on yourself to prime your skin. It tingles.
You rub chalk powder on yourself while considering its rock-like nature.
You rub varnish on yourself to bind it all together. It feels strangely cold.
You feel your skin become rock-hard.

Help Information:

Chrenedict's Calcareous Covering - Stone skin.

Chrenedict's Calcareous Covering is a second order defensive spell which temporarily gives the target skin  like that of a sedimentary troll.