31. One such mineral that is useful is apatite . 32. Turquoise may also pseudomorphously replace feldspar, apatite , other minerals, or even fossils. 33. John Weber and his associates presented fission track dating of apatite from this impact structure. 34. The accessory minerals of these rocks are principally oligoclase, muscovite, apatite and zircon. 35. In the west of the town slate enriched by apatite and zircon can be found. 36. Initially, phosphate weathers from rocks and minerals, the most common mineral being apatite . 37. It is a member of the apatite group, and forms a series with hydroxylellestadite. 38. Portnoy was keen to find something more unusual, a tourmaline or perhaps some green apatite . 39. Citrate is a vital component of bone, helping to regulate the size of apatite crystals. 40. Apatite is one of a few minerals produced and used by biological micro-environmental systems.
