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Volume 66, pages 885-908, 1981

The largest crystals

PETER C. RICKWOOD

School of used Geology

University of brand-new South Wales

Kensington, N. S. W. 2033, Australia

Abstract

No top limit top top the dimension of crystals is to be expected, butthe dimensions and also occurrences of the largest well-known crystals in every of twenty-four category (nine classes) ofminerals space presented and also discussed. The largest authenticated crystal of any kind is a beryl native Malakialina,Malagasy Republic, gift 18 m in length, 3.5 m in diameter, having a volume estimated at 143 m3 and a massive approximately380,000 kg.

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Introduction

Palache (1923) wrote, "How large can crystals grow? What teacher the mineralogy yet has beenasked this question plenty of times. He would most likely reply the there is no limit yet if the tried to tell that the biggestthat had been discovered he would uncover it difficult to give precise answer". Among the plenty of improbable story handeddown from college student to student is the story that a mysterious locality in the Urals whereby a quarry to be made within a singlefeldspar crystal. And yet there may be fact in this, for the undocumented report of such an orthoclase crystal can betraced to Lindgren (1933, p.754). Its size was offered by Hurlbut (1968, p.14) thus ". . . In the Ural hills aquarry 30 x 30feet the unknown depth was opened up in a single feldspar crystal", and also Kostov (1968, p.55) composed "There areknown, . . . Orthoclase crystals 10 m x 10m weighing up to 100 tons, . . ." Regrettably, like plenty of giant crystals the was no accurately measured, so its truedimensions stay unknown.

much more than fifty percent a century has actually passed due to the fact that Palache (1923) published, in this journal, a perform of thelargest crystals known to him, and also wrote "Will not every leader of this magazine supply together data as hepossesses?" The plea must have been, unheeded for an updated perform did no appear, although Spencer (1928), Frondel(1935), and also Jahns (1953) subsequently recorded added data on large crystals of minerals which were of particularinterest to them. A much more recent appeal (Rickwood, 1976) because that such data was likewise rewarded with little response. Anextensive literature search, and a multitude of letter to mineralogists transparent the world, has, however, yielded lot data i beg your pardon is presented below for it has actually neverpreviously been brought together in a solitary compilation.The Compilation

How best to present this data has actually been a problem for a list consisting of every mineral species, together asPalache (1923) commenced to compile, would have actually been both cumbersome and also extremely challenging to produce.Accordingly, this compilation gives (Table 1) the largest recognized crystals for each of the mineral great in theclassification supplied by Mason and Berry (1968, p.197). Every of the compositions called in their class titles has actually beenseparately listed and the most common minerals - silicates - have been considered by subclasses. In addition, some data fororganic minerals space presented.

because that each the the twenty-four mineral categories, there are noted in Table 1 the crystals which havethe biggest length, the greatest volume, and also the best mass. Sometimes a solitary crystal has actually all three records, butmultiple entries because that a category have regularly proved essential to incorporate these and also establish the documents in thatsequence. Extr specimens are also provided whenever a larger crystal has actually been incompletely documented, or wheredoubt exists that it is a single crystal. Every data are offered in SI units with converted dimensions being indicated byan asterisk and also estimated or calculated parameters gift enclosed by parentheses. Convert measurements have actually beenrounded to the nearest centimeter (or two far-ranging figures) and calculations of volume and also mass have been based on the rounded figures, assumingsimple geometrical shapes.For each crystal, only the initial reference iscited unless it is in a fairly obscure publication, or a later paperincludes extr data. Number of measurements have actually been obtained from the publication by Sinkankas (1964), however this writer did not cite thedata resources so this information could not it is in verified. Publications by Guillemin (1964, 1972) are lists the selected specimens contained in assorted museumcollections and also were most beneficial sources of information. However, occasional inequalities in dimensions have actually beennoticed between data provided by Guillemin and also that supplied by curators. In these instances the information noted bymuseum curators has actually been preferred. Keep in mind that Guillemin (1964) renumbered the pages for each museum so that it isnecessary to understand the location of the crystal prior to data can be retrieved.

The crystals recorded below merit inclusion by virtue of their size and also not their beauty. Undoubtedly manyof these large crystals have irregular type and small aesthetic appeal. Very huge crystals deserve to be difficult, if notimpossible, to accurately measure uneven they are totally mined the end of their matrix. Seldom would a geologist bepresent throughout such an operation and so, the necessity, some dimensions may have actually been acquired from miners. The isalso challenging to ascertain that these are single entities and also not aggregates of smaller crystals. Hence, uneven anauthor has specifically suggested that the material is a single crystal, there has been a aware rejection that alldata top top "masses", "aggregates", "deposits", "shoots", "pods", etc.

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Notes ~ above entries in Table 1 Almost every one of the entries in Table 1 call for comment and to avoid substantial list the footnotesthese comment are included in the text. The alphabet designation signifies the mineral category to i beg your pardon the commentrelates, and the subscript numeral suggests the certain entry.