The Apatite is a phosphatic mineral, mostly opaque, often transparent, or more rarely secondary magmatic origin.
And 'highly fluorescent and is often used as a gemstone cabochon cut.
The Apatites are part of an important family of minerals and different types if they differ according to their chemical conformation: idroapatite, chlorapatite and fluorapatite.
In the past it was often confused with other minerals such as beryl and Calcite. Only in 1786 was identified and received its current name, which, significantly, is derived from the greek word "Apatao" which means fool.
So you do not have information of any kind for what concerns its uses in the medical or scientific prior to this date.
In the past it was used mainly used for the construction of cathode ray tubes with fluorescence to phosphorus, but now practically in disuse.
The fact that it was confused with other minerals has not led to know the real uses in the past.