Q: story or series of humans who can control elements due to exposure or ingestion of crystals Saw this book or series on a shelf of a mall store probably in the 80's. Prologue described a war between groups of humans. By exposure or ingestion of some sort of crytal they could control an element like wind or fire. Crystals are sentient. Attempt to control more than one element is fatal because first crystal attacks the second. Main character gets exposed to all crystals at once in a battle to prevent someone else from getting the crystals and successfully gets control of all elements. Crystals had a name...something like sathid. Does anyone recognize the name of the series or book from the plot? 

A: The Sathid are indeed sentient crystals in Yanny Wurts' series The Cycle of Fire, however I don't think these books match the rest of your description and the first book Stormwarden was published in 1990. The Cycle of Fire books are about a war between humanity and demons, and more than one crystal can be ingested though trying to master more than one crystal is dangerous as the strength of more than one crystal can be great enough to possess you.
I wonder if you've conflated the Cycle of Fire books with another series.
