The same article you posted also says this.
"That being said, the emerging wearable and Internet of Things (IoT) market is likely to be a secular driver of sapphire demand. The technology appears to be in the nascent stages and, in fact, Apple is increasingly investing in the manufacture of the material and has also acquired exclusive licenses of some of GT Advanced’s technologies."
I can only provide my own speculation and theories. I am not qualified to offer any investment advice. Everything I post is my own opinion. Please research all stocks before investing. My posts are my opinions and are not buy or sell recommendations.