The best example of this habit is the "Apatite
H," 7.5 X 16 cm, formed by three attached clusters (the longest measuring 13.5 cm) aligned almost perpendicularly to each other.
1996) as that of sedimentary apatite
with different levels of fluoride, carbonate, magnesium, and cadmium substitutions were prepared by precipitation from aqueous solution at 80[degrees]C.
Calculations of apatite
unit-cell a and c dimensions were derived from XRD patterns using an iterative least-squares computer software (Novak and Colville 1989).
For the Zn-Ca apatites
with lower [X.sub.Zn] or higher [X.sub.Ca], the solution [Ca.sup.2+] concentrations increased quickly with time and reached the highest values after 24-480 h dissolution.
1999) and has been reported to reflect equilibrium fractionation between the biogenic apatite
and the slightly anoxic or suboxic bottom seawater of that time (see Patrick et al.
Bhatnagar, "X-Ray and infrared studies of lead apatites
," Canadian Journal of Chemistry, vol.
Ceramic samples of silicate apatites
[M.sub.2][Ln.sub.8][(Si[O.sub.4]).sub.6][O.sub.2] (M = Mg, Ca, Sr; Ln = Y, La) undoped and doped with [Eu.sup.3+] (0.5, 1.0, and 2.0 at.%), [Ce.sup.3+] (0.5 at.%) or [Mn.sup.2+] (1.0 at%) were synthesized by a high-temperature solid-state reaction at 1300 [degrees]C for 10 h upon using precursors obtained under hydrothermal conditions .
Rare earth element evolution of Phanerozoic seawater recorded in biogenic apatites
. Chemical Geology, 204, 64-102.
Fluorapatite is known to be much more stable and resistant to acid dissolution as compared to hydroxy- apatite
Green, P.F.: 1981, 'Track-in track' length measurements in annealed apatites
. Nuclear Tracks, 5, 121-128.
It can be seen that the samples have been covered by apatite
cell since first day Fig.