From LSWiki

Kacha Biocrystal Array

   This is an array of kacha columns.  This is a biocrystal array, a kind of
   symbiotic armour.  The array embeds itself in the wearer's flesh and draws on the
   magick in hir blood to protect hir and sustain itself; over time, it expands to
   cover more and more of the wearer's body.  The process of implanting the crystals is
   simple, if painful and even dangerous; once implanted, they require special
   procedures to remove.  It is permeated by a dim shimmering radiance.  You estimate
   that it is worth something upward of four thousand five hundred gold.  You are
   implanting it.  
   
   It is in perfect condition.  
   
   It is huge in size, and looks a little large for you.  It looks about
   twenty-nine and a half dimins tall, about eight and seventeen twentieths dimins
   wide, about two and nineteen twentieths dimins long, and less than a twentieth of a
   dimin thick.  It weighs about ten and a half dekans.

Notes

This works as epidermal armor, implanted under the skin of the user. If the user loses a limb, there may be consequences as the rest of the array is forcibly de-implanted.

While implanted, this provides some armor, a +200 bonus to Crystal Affinity and an undetermined bonus to Crushing Resistance. (may be cutting resistance, did not have knowledge of either resistance skill to verify)

Spoilers

If you'd like to acquire a set of your own, there is a forgotten ruin on another plane that might be worth a closer look.