| The MP2 Research Group Abstracts | |
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Introduction: |
 |  Recent finds of beautiful blue and purple fluorapatite from the Emmons and Harvard pegmatites are some of the best examples of royal purple apatite recovered from Maine pegmatites in recent times. The crystals occur principally in vugs in altered beryl crystals and are associated with a replacement assemblage of bertrandite, cookeite, and Fe/Mn oxide pseudomorphs after siderite/rhodochrosite. |
| Exhibits: Exhibit A: Olive-green, blue, lilac, white, and colorless fluorapatites occur within beryl casts as well a on cleavelandite in miarolitic cavities. A correlation between crystal morphology and color has been observed. Olive-green crystals tend to form simple elongate or stubby prisms with pinacoids. Blue crystals have similar morphology, but shorter aspect ratios. |  |
| Exhibit B: SEM Colorless crystals tend to be more tabular with modifications by the dipyramids and other forms. Purple and lilac fluorapatites tend to occur as more complex, almost equidimensional crystals with short prismatic or thick tabular morphology. |  |
| Exhibit C: Fluorapatites from the Emmons pegmatite may show very complex and beautiful zoning patterns with oscillatory zones, chaotic zoning, as well as areas exhibiting partial dissolution with later overgrowth. |  |
| Exhibit D: All fluorapatites analyzed are close to end-member fluorapatite, Ca5(PO4)3F with a wide range of Mn and Sr impurities. The highest observed content of SrO exceeds 20 wt%. Generally, however, SrO contents range from 0 to several wt%. No consistent relationship between color hue and minor element content of chromophoric ions such as Mn and Fe was found. Evidently other factors, such as structural defects, are probably responsible for the beautiful colors of these fluorapatites. The widespread, and in some cases, the high Sr content of these fluorapatites indicates a significant Sr content in the parental pegmatitic melts. |  |
| Exhibit E: X-ray linescans of the three elements Mn, Fe, and Sr across several differently colored apatites from Maine pegmatites, including the Emmons Quarry pegmatite. |  |
Conclusions: |
| Correlation Between Morphology & Color of Emmons Quarry Fluorapatite | ||
| Olive-green crystals | Simple elongate or stubby prisms w/ pinacoids. | |
| Blue crystals | Similar but shorter aspect ratios. | |
| Colorless crystals | More tabular w/ modified dipyramids & other forms. | |
| Gray crystals | Longer aspect ratios w/ more dominant dipyramids, capped by smaller pinacoids. | |
| Lilac crystals | More complex. Equant, short prismatic & thick tabular morphologies. | |
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