Color: blue, green, yellow, pink, violet, colorless.
Moh’s Hardness: 5
Refractive Index: 1.632-1.646
Critical Angle: 37.84°
Specific Gravity: 3.17-3.23
Cleavage: Poor, imperfect
Fracture: Conchoidal, brittle
Heat Sensitivity: High
Dichroic: Strong to weak depending on the color
Birefringence (double refraction): Weak (.002-.004)
Crystal Structure: Hexagonal
Treatments: Blue/green, blue Apatite is usually heat treated to bring out the blue color and to remove silk.
What I prefer to polishing with: Alumina oxide and a tin lap, Spectra Untralaps work well too,vinegar can ease polishing difficulties. I use it straight (no water), just a few drops of vinegar and polish…
Jeff’s Comments: This material is difficult to get clean and any decent size. The crystals are typically included and the cleavage can be quite a problem. Cold dop only, heat can cause the cleavage to run…
Use a fine lap, like a worn 600 to rough in… It cuts fairly easily and is quite different, polishing is where you will run into problems. It can be brittle, sharp corners may chip because of brittleness and just hard to get a scratch free polish.
I like the color of this material but it is basically a novelty stone, it is too soft to set in jewelry as a general rule.