American Mineralogist, Volume 66, pages 885'907' l98I The largest crystals PEreR C. Rtcrwooo Schoolof Applied Geologlt (Jniversityof New South |l'ales Kensington,N. S.W. 2033, Australia Abstract No upper limit on the sizeof crystalsis to be expected,-butthe dimensionsand occurrences of the largestknown crystalsin each of twenty-four categories(nine classes)of minerals are presentedand discussed.The largestauthenticated brystal of any type is a beryl from Mala- katna, MalagasyRepublic, being l8 m in length, 3.5 m in diameter,having a volume esti- mated at 143m3 and a massapproximately 380'000 kg. Introduction throughout the world, has, however, yielded much data which is presentedhere for it has never pre- Palache (1923) wrote, "How large can crystals viously been brought together in a single com- grow? What teacher of mineralogy but has been pilation. askedthis questionmany times. He would probably is no limit but if he tried to tell of the reply that there The ComPilation biggest that had been found he would find it difficult a problem to give an exact answer". Among the many improb- How best to presentthis data has been such as Pa- able taleshanded down from studentto studentis the for a list including every mineral species, would have story of a mysterious locality in the Urals where a lache (1923) commenced to compile, to quarry was made inside a single feldspar crystal. And been both cumbersomeand extremely difficult gives (Table yet there may be truth in this, for the undocumented produce. Accordingly, this compilation the mineral report of such an orthoclasecrystal can be traced to t; th" lutg"tt known crystalsfor each of and Berry Lindgren (1933,p.754). Its sizewas given by Hurlbut classesin the classificationused by Mason named in (1968,p.14) thus ". in the Ural Mountains a quarry (1968,p.197). Each of the compositions listed and the 30 x 30 feet of unknown depth was opened in a iheir class titles has been separately been con- single feldspar crystal", and Kostov (1968, p.55) most common minerals-silicates-have data for or- wrote "There are known, . orthoclasecrystals l0 m sideredby subclasses.In addition' some x l0 m weighing up to 100 tons,.. ." Regrettably, ganic minerals are Presented. categories, like many giant crystalsit was not accurately mea- For each of the twenty-four mineral which have the sured, so its true dimensions remain unknown. there are listed in Table I the crystals greatest More than half a century has passedsince Palache greatestlength, the greatestvolume, and the rec- (1923)published, in this journal, a list of the largest mass. Sometimesa single crystal has all three have often crystals known to him, and wrote "Will not every ords, but multiple entries for a category establish reader of this magazinesupply such data as he pos- proved necessaryto encompassthese and specimens sesses?"The plea must have been unheededfor an ihe records in that sequence.Additional has been in- updatedlist did not appear,although Spencer(1928)' are also listed whenevera larger crystal existsthat it Frondel (1935),and Jahns (1953)subsequently re- completelydocumented, or where doubt given in SI units with corded additional data on large crystalsof minerals is a single crystal. All data are by an aster- which were of particular interestto them. A more re- convertedmeasurements being indicated parametersbeing en- cent appeal (Rickwood, 1976)for such data was also isk and estimatedor calculated measurements rewardedwith fittte response.An extensiveliterature closed by parentheses.Converted (or two signifi- search, and a multitude of letters to mineralogists have been rounded to the nearestcm 0003-004x/8l /09 I 0-088s$02.00 885 EE6 RICKWOOD: LARGEST CRYSTALS Table l. The largest crystals of minerals CLASS ASSIITIED DIMENSIoNS(n) VOU'IIIE I{ASS DEI{S-MT REFERENCES lxzx3(n3)(kg) (g/-3) I. MTIVE ELEMEN'IS a, Kmacite (q -ircn - alloy) 0.92 0.54 0.23- (o.03E) g3 (7.9o) FESENKOV(rgsE) Fe-Ni 0.13 Gressk, MiEk oblast, u.s.s.R. a2 cold *0.30 -Au (r9.3) STNXANXAS(r96EPp.27E 2w) Mother Lode, Cali fomia, u.s.A. a< Sulphur 0.225 0. 165 (<0.0025) (<s. 14) (2.05) de MIGIELE (Pes. 5 Cm.22. ro. 79) PerticaE Mine, Urbino, (Figur 1) Italy. 2. SULPIiIDES € SULPHOSALTS (i)SULTHIDES € RELAIED COilPOIJNN bl stibnite ' 0.60 0.0s (0.0s) (0.001s) (6.ss) (4.63) flADA(1904,p.2r). sb2s3 PATACHE(1923,p.362). Yokohi Mines, Ichinokawa, Shikoku Island, Iyo Prcvince, Japan, b? Stibnite - O.S8S 0.057 0.048 (0.00r6) (7.4r) (4.63) }|ANISct (Pors,Cm, sb2s3 rE. I.50) (Figuro 2) Ichinokara, Iyo, Shikoku, Japan. b. Galena *0,25 0.25 0.25 c0.01s61 (rr8) c7.56) GREG6 r.ETTS6l " Pbs (r8sE, p.41s). Great Luey lr{ine, Isle PAIAGIE [r923,p.362). of lr{an,U.K. (Ftgue 5) (ii)SULPH6ALTS cr Tenkntite - 0.3O (o. @3rE) (14.7') (4.61) (Cu,Fe) PIN(I & HIT,soN l2As4Sr3 (1977,p.33) Tsmeb, Nmibia c? Arp.rodite - 0. lE 0,I5 8.12 (0.00324) (20.0e) (6.2) cUILLEWN(1964,p.1) Ag8GeS6 (1972,p.rrs). Bolivia OXIDES AND HYDROXIDES (i) OXIDES -1 Coludite *0.76 0.61 <0.0064 :0.00297) ( ls, 4) (s.2) H NTEY(r9s5,p.77) ( Fe , N'l) (Nb , Ta) 206 PAGE(PeE.Cm. Bob Ingersoll l{ine, 6.6.E0) Dike No.l, Black Hills, S.Dakota, U.S.A. dz Corodm 0.65 0. 40 (0.03s6) '152 (5.98) IIALL (1920,p.128, Al2 03 (diil) PTATE XXI) nr.Mica Sidins. PAIA(}|E(1923,p. 363) Transvaal, R.5.A. (FIGURE4.) cant figures) and calculations of volume and mass later paper includes additional data. Several mea- have been based on the rounded figures, assuming surements have been obtained from the book by simple geometricalshapes. Sinkankas (1964\, but this author did not cire the For each crystal, only the original reference is data sourcesso this information could not be veri- cited unlessit is in a rather obscurepublicatron, or a fied. Books by Guillemin (1964, 1972)arc lisrs of se- RICKWOOD LARGEST CRYSTALS lected specimenscontained in various museum col- literature (Dana and Brush, 1812, p.l5; Hurlbut, lectionsand were most useful sourcesof information. 1968,p.156; Murdoch, 1943;Palache et al., 1944, However, occasionaldiscrepancies in dimensions p.l0l) as having been found in the Copper Range, have been noticed betweendata given by Guillemin Keweenaw Peninsula, Michigan, U.S.A' However, and that supplied by curators.In theseinstances the Mr. A.Y. Johnstone(Pers. Comm.20.5.77) noted that information provided by museum curators has been thesewere almost certainly crystal aggregatesand the preferred. Note that Guillemin (1964) renumbered largest of the rare single crystals from the area was the pagesfor each museum so that it is necessaryto only 4.4 x 3.2 x 3.2 cm. know the location of the crystal before data can be L3 This crystal (Fig. l) is in the collection of retrieved. the Museo Civico di Storia Naturale, Milan, Italy. A The crystalsrecorded here merit inclusion by vir- sketch supplied by Dr. V. de Michele (Pers.Comm. ture of their size and not their beauty. Indeed many 22.10J9) gives the listed dinensions which are more of these large crystalshave irregular form and little accurate than those given by Guillemin (1964, p.l; aestheticappeal. Very large crystalscan be difficult, 1972,p.5) and de Michele(1978, p.42). A smallpatch if not impossible,to accuratelymeasure unless they of calcite adheres to the sulphur so that the true are completely mined out of their matrix. Seldom weight is not known. would a geologistbe presentthroughout such an op- Other notable sulphur crystalsare: eration and so, of necessity,some dimensions may (i) one 18 cm long from Perticara,Urbino, Italy have been obtained from miners. It is also difficult to and kept in the Institute of Mineralogy, Milan, Italy; ascertainthat theseare single entities and not aggre- Guillemin (1964,p.l). gatesof smallercrystals. Hence, unless an author has specifically indicated that the material is a single crystal, there has been a consciousrejection of all data on "masses","aggregates", "deposits'n, "shoots", "pods", etc. Notes on entriesin Table I Almost all of the entries in Table I require com- ment and to avoid an extensivelist of footnotesthese comments are included in the text. The alphabetic designation signifies the mineral category to which the comment relates,and the subscript numeral in- dicates the specific entry. Dimensions published in Imperial units have been converted to metric units and are given in parenthesesin thesenotes. o1 This specimenis "... a monocrystalhex- ahedrite , .." being describedas "an irregular bowl- shaped mass, with an overall length of 92 cm and a width of 54 cm: it attains a thicknessof about 23 cm along the edgesbut is only 13 cm thick near the cen- ter". (Dr. B. Mason,Pers. Comm.3.l.79). The density of kamacite was found by Henderson and Parry (1954)to be 7.90+0.02g/cm'. As this is extraterrestrialmaterial, this entry is ad- ditional to those of terrestrial minerals. d2 Sinkankas(1964, p.280) mentioned ". oc- tahedral plates to 12" broad. ." (0.30 m) from an unspecifiedlocation in California, but the Curator, (terrestrial) NATIVE Mineral Museum, Division of Mines and Geology, Fig. L The largest authenticated ELEMENa| crystal by length, volume and mass. Sulphur, Stateof California, U.S.A. cannotconfirm this occur- PerticaraMine, Urbino, Italy. This photographhas been supplied rence.(Mrs. E.M. Learned,Pers. Comm. 28.9.79). by, and is producedby permissionof, Dr. V. de Michele, Museo Very large specimensof copperare recordedin the Civico di Storia Naturale, Milan, Italy (Table 1-a3).