Tachydrite or Tachhydrite: How To spell?

The word Tachydrite is misspelled against Tachhydrite, a noun meaning "A hydrous chloride of calcium and magnesium occurring in yellowish masses which rapidly deliquesce upon exposure. It is found in the salt mines at Stassfurt."

Tachhydrite has double "hh" is mispronounced as "h"
Remember double 'HH' in between the strings tac & ydrite which should not be misspelled with single 'H'
Wrong Spelling:  tac-h-ydrite 
Correct Spelling:  tac-hh-ydrite 
Find more wrongly spelled words of Tachhydrite to spell it well.