NOMENCLATURE REVISIONS IN

THEA POPHYLLITE GROUP:HYDROXYAPOPHYLLITEAPOPHYLLITEFLUORAPOPHYLLITE

by

Pete J. DunnDepartment of Mineral Sciences

Smithsonian InstitutionWashington, D.C. 20560

andWendell E. Wilson

The Mineralogical RecordP.O. Box 783, Bowie, MD 20715

INTRODUCTIONApophyllite, KCa4Sis020(F,OH )'8H20, is a rather common

mineral and is found in a variety of rock types, most commonlyin volcanic rocks and limestones and marbles, but also as a late-stage deposition in ore deposits. The recent discovery of the(OH) analog of apophyllite (Dunn et al., 1977) has resulted ina revision of the nomenclature. The IMA (International Min-eralogical Association) Commission on New Minerals and Min-erai Names has voted on this revision and the nomenclatureapproved by the Commission is as follows:HYDROXYAPOPHYLLITE-for material with hydroxyl

greater than fluorine.FLUORAPOPHYLLITE - for material with fluorine

greater than hydroxyl.A POPHYLLITE -for undetermined members

of the group.This paper was written to acquaint the collector and curator

with the correct nomenclature and to provide information on"apophyllite" specimens from specific and general localities.

NOMENCLA TURE#ISTORYApophyllite was apparently first mentioned by C. Rinman

in 1784, as one of the "zeolites" (sic) from Hellesra, Denmark.It was again noted by MUller in 1791, as a "major lamellar zeo-lite" in his work, De Zeolithus Suecicis. The first name givenit was ichihyophthalmite (Greek for "fish-eye rock") in referenceto the pearly white luster which resembled that of a fish-eyeafter boiling. This name was applied by d'Andrada in 1800, tomaterial from Uta, Sweden. In 1801, Hauy gave the name meso-type epoinlee to apophyllite from Iceland, and four years latergave the name apophyllite ("leaf rock") to material from a dif-ferent locality, in allusion to its tendency to exfoliate underthe blowpipe.

Other names continued to be proposed for a few years. Wer-ner called it fischaugenstein (German for "fish-eye rock") in1808. In 1816 Fuchs and Gehlen showed that HaUy'smesotypeep ointee was identical to his apophyllite. In 1817, Werner de-scribed a variety called albin ("white"), in small white crystalsfrom Aussig, Bohemia; the material was partially decomposedand consisted largely of calcite. Brewster described in 1819 avariety he called/ish-eye stone tesselite,frorn the Faeroe Islands,

The Mineralogical Record, March-April, 1978

because it exhibited a tesselated structure in polarized light.In 1820, Herschel read a paper before the Cambridge Philosophi-cal Society describing a mineral he called leucocyclite ("whitering") because of the pattern formed by polarized light underthe microscope; this also proved to be apophyllite. In 1827,Brewster described another variety, which he called oxhaverite,from Oxhaver Springs, near Husavic, Iceland. Still anothervariety, colored olive-green by a trace of iron, was describedfrom Sicily by von Waltman in 1853; he called it xylochlor("wood-green"). (See Dana's System 0/ Mineralogy, 1904, sixthedition, p. 566-569, for full references.)

NEW NOMENCLA TUREHYDROXYAPOPHYLLITE

Hydroxyapophyllite, KCa4Sis020(OH)·8H20, is the hydroxylanalog of fluorapophyllite, KCa4Sis020(F)·8H20. The type lo-cality for the new species is the are Knob mine, Jefferson, AsheCounty, North Carolina. At this locality, the hydroxyapophylliteoccurs as 1.0 em thick druses of white crystals overlying a chalco-pyrite-pyrrhotite assemblage. The mineral occurs as crusts onspecimens up to 15 x 15 em.

Hydroxyapophyllite is not distinguishable from fluorapophyl-lite by means of visual examination, X-ray studies or, in mostcases, optical examination. For this reason, it is quite difficultfor the collector to ascertain which species may be present ona given specimen. To assist the collector and curator, a largenumber of "apophyllite" specimens were analyzed with an elec-tron microprobe to determine their fluorine content and, thus,their correct nomenclature.

In addition to the type locality, two other localities have pro-duced specimens which are consistently hydroxyapophyllite.One of these, Kimberley, South Africa, has produced a numberof specimens over the years, but not in any great quantity, tothe best of the author's knowledge. The crystals occur up to6 ern, although most are considerably smaller. They are whiteor colorless and not distinguishable from common "apophyllite",

A third locality for hydroxyapophyllite is, much to the mineralcollector's delight, a locality which has produced, over the years,a considerable number of fine specimens of hydroxyapophyllitewhich are frequently associated with pale violet amethyst. Thislocality, Guanajuato, Mexico, produces both hydroxyapophyllite

95

Figure 1. Hydroxyapophyllite from the typelocality, the Ore Knob mine, Jefferson, AsheCounty, North Carolina. The crystals arewhite and 5 to 6 mm in size. Smithsonianspecimen #121689.

96

Figure 2. Hydroxyapophyllite from Kimber-ley, South Africa. The white crystals are upto 2 em in size. Smithsonian specimen #93040.

Figure 3. Hydroxyapophyllite (with gyrolite)from Khandivali, near Bombay, India. Thecrystals are white; the largest is 1.3 cm on anedge. Smithsonian specimen #136898.

Figure 5. Fluorapophyllite from Paterson,New Jersey. The crystals have inclusions of agreen fibrous mineral; the top crystal is 2 emacross. Smithsonian specimen #R4031.

Figure 4. Fluorapophyllite from West Pater-son, New Jersey. The crystals are colorlessand measure 1.7 em on an edge. Smithsonianspecimen #RI4714.

The Mineralogical Record, March ~ April, 1978

Figure 6. Fluorapophyllite from Khadakvasla,Poona district, India. The crystals are lightgreen in color; the specimen is 7.5 em wide.Smithsonian specimen #R18158.

The Mineralogical Record, March - April, 1978

Figure 7. FluorapophylUte from Nasik, India.The crystal is colorless. 2.2 ern tall, on a ma-trix of pink stilbite. Smithsonian specimen#126692.

Figure 8. Fluor apophvllite from the BergenHill area, lew Jersey. The crystals are color-less, up to 2.5 ern across, with analcime ondatolite. Smithsonian specimen #116071.

Figure 9. Fluorapophyllite from AhmedNagar, India. The crystal is a very pale greenin color and about 2 cm tall. Smithsonianspecimen #126691.

Figure 10. Apophyllite (in mixed crystals oftranslucent hydroxyapophyllite and f1uora-pophyllite) from the Fairfax quarry, Centre-ville, Virginia. Both specimens are a very palecream color; the crystal on the left is Smith-sonian specimen #127843; the crystal on theright is Smithsonian specimen #R17088 and is6 em tall.

97

and fluorapophyllite. but hydroxyapophyllite is the more com-mon on the specimens examined, and, for consistency, it is bestthat all Guanajuaro specimens be labeled hydroxyapophyllite.This locality has produced many specimens with crystals upto 3 x 1 x 1 cm. Some are tinged with a pink or violet cast, butmost are white. The pearly luster on {OOI} is well developed,and the crystals exhibit the characteristic morphology of com-mon apophyllite with the prism {IOO} striated parallel to c, andthe imple dipyramid {lll} well developed. These are the mostbeautiful b droxyapophyllite specimens known. Altbough theexact locality is not known with certainty, the material is stillavailable in some dealers' stocks and frequently re-appears whenold collections are broken up and redistributed.

fourth locality for hydroxyapophyllite is Khandivali, nearBombay, India. Specimens from this locality, together with somefrom the Parvati Hills, near Bombay, proved to be the (OH)member. Inasmuch as this material is still available, collectorsand curators seeking specimens of this species should be able toobtain them with little difficulty from leading mineral dealersand at mineral shows.FLUORAPOPHYLLITE

Fluorapophyllite is herein defined as material with fluorinegreater than hydroxyl. Analyses of many specimens in the searchfor the (OH) end-member resulted in the following general ob-servations regarding the correct nomenclature for specimensfrom specific and general localities.

New Jersey. The preponderance of the specimens from thePaterson, New Jersey area are fluorapophyllite. Specimens fromthe Bergen Hill area, and Prospect Park, in New Jersey. are, forthe most part, fluorapophylJite. Several opaque, white, chalky

crystals from the latter two localities are hydroxyapophylJite.India. Specimens from the Poona district, from Nasik, and

from the Ahmed Nagar district are fluorapophyllite. The speci-mens studied were all from material which has been importedduring the last ten years.

Many other localities were briefly examined in the searchfor the (OH) end-member. However, one or two analyses arenot necessarily indicative of the composition of all apophyllitefrom a given locality. The fine crystals from the Centreville.Virginia locality (Medici, 1972) are neither end-member butare, for the most part, physical mixtures, with both phases oc-curring within a given "crystal". These Centreville crystals,together with apophyllite from other localities not studied indetail, should be called apophyllite. Apophyllite is still a validmineral name for all specimens which bave not been determinedto be either end-member.

It is neither possible, nor desirable, for the authors to examinespecimens for collectors to determine their correct speciesnames. The IMA Commission ruling clearly states that all un-known material should be called apophyllite. We sincerely hopethat the information contained herein is of use to collectorsand curators.

REFERENCESDUNN, PJ., ROUSE, x.c.. NORBERG, J.A. (1977) Hydroxya-

pophyllite, a new mineral, and a redefinition of the apophyllitegroup. Part 1. Description, occurrences, and nomenclature.A merican Mineralogist, 62, 196-202.

MEDICI, J.c. (1972) Minerals of the Fairfax quarry, Centreville.Virginia. Mineralogical Record, 3, 171-179. ~

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