The word "Masticine" is spelled with the letter "c", which can be confusing due to its pronunciation. In IPA phonetic transcription, it is spelled /ˈmæstɪˌsaɪn/. The "c" is pronounced as "s" in this case, as it is followed by "i". We can also notice the "ine" at the end, which suggests a suffix often used for substances, indicating that "Masticine" may refer to some kind of material or compound. With proper understanding of the spelling and pronunciation, we can use this word confidently.
The portion of mastic insoluble in alcohol.
Etymological and pronouncing dictionary of the English language. By Stormonth, James, Phelp, P. H. Published 1874.