Meionite



Meionite is a calcium sodium aluminum silicate carbonate mineral of the scapolite group. The chemical compositions of some local scapolites were reported by Frondel (1972) to be intermediate between those of marialite and meionite, a result confirmed by Kearns (1977) for scapolites in general from the Franklin Marble in New York. The meionite designation used here is based on numerous partial analyses by [Dunn]. The preponderance of Franklin scapolites contain from 50-64 mole % meionite. Marialite occurs here as well, but is rare.
Scapolites from Franklin were known to Nuttall (1822) and Nason (1890b). The extant data were summarized by Palache (1935) and Frondel (1972), but are very sparse. There exists a substantial literature on the alteration products of scapolite, once named algerite and kembleite; these were the subject of numerous discussions by Hunt (1849, 1850, 1854), Crossley (1850), Jackson (1850c), and Dana (1853, 1854). Local scapolites are mostly calcium-rich and are the meionite member of the scapolite group.
Fine meionite crystals occur in stout prisms up to 8x10 cm, but have not been studied. Franklin meionites are generally colorless to light yellow or light green; fine-grained violet material is also known. The luster is vitreous; cleavages are good to imperfect; and it is fluorescent in longwave ultraviolet with red, pink, orange, and yellow response colors (Bostwick, 1982).
Meionite is moderately common throughout the northern part of the Franklin Marble in New York (Kearns, 1977) and in the Franklin area. In addition to isolated occurrences within the Franklin Marble, it is found at marble contacts with the Franklin orebody.
Local meionite is associated with calcite, microcline, molybdenite, graphite, garnet, phlogopite, titanite, spinel, and other species. Most notable are rare, fine pseudomorphs in which 5 cm scapolite crystals are replaced by bright green epidote; this material is associated with a dark colored, unanalyzed garnet. A non-type specimen labeled algerite, and fitting the description of that material, was found by [Dunn] to be largely mica. Unanalyzed scapolite is known from the Sterling Hill orebody. (Dunn, 1995)


 Location Found: Franklin and Ogdensburg
     
 
 Year Discovered: 1801
     
 Formula: Ca4Al6Si6O24CO3
 Essential Elements: Aluminum, Calcium, Carbon, Oxygen, Silicon
 All Elements in Formula: Aluminum, Calcium, Carbon, Oxygen, Silicon
     
 IMA Status: Valid - first described prior to 1959 (pre-IMA) - "Grandfathered"
     
Fluorescent Mineral Properties

 Shortwave UV light: Pinkish red, cherry-red, or orange-yellow
 Mid wave UV light: Pinkish red, cherry-red, or orange-yellow
 Longwave UV light: Moderately bright to weak orange-yellow , weak blue
     
 To find out more about this mineral at minDat's website, follow this link   Meionite

     
 References:
Dunn, Pete J. (1995). Franklin and Sterling Hill New Jersey: the world's most magnificent mineral deposits. Franklin, NJ.: The Franklin-Ogdensburg Mineralogical Society. p.512


The Picking Table References
 PT Issue and PageDescription / Comment
V. 58, No. 1 - Spring 2017, pg. 13Fluorescent Minerals of Franklin and Sterling Hill, N.J., Part 2, Richard C. Bostwick - Meionite
View IssueV. 33, No. 2 - Fall 1992, pg. 11The Check List of Franklin-Sterling Hill Fluorescent Minerals - Meionite (Fluorescent Info)
View IssueV. 27 No. 2 - Fall 1986, pg. 7Minerals of the Franklin Quarry, Philip P. Betancourt, Scapolite Group (meionite?)
     
Images

     
Meionite, calcite, franklinite and galena from Sterling Hill Mine, NJ.Meionite, calcite, franklinite and galena from Sterling Hill Mine, NJ. under shortwave UV Light
Meionite, calcite, franklinite and galena (gray, left side) from Sterling Hill Mine, NJ. Photo by WP.
Meionite, calcite, franklinite and galena from Sterling Hill Mine, NJ under shortwave UV light. The meionite fluoresces dark pink to magenta and calcite red-orange, the franklinite and galena are non-fluorescent. Photo by WP.







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