E. T. Wherry — Amphisymmetric Crystals. 243 



recent X-ray study has shown the structure to be holo- 

 symmetric, making it now possible to be more specific: 

 "Tetragonal; structurally holosymmetric ; latently 

 pyramidal. ' ' 



In conclusion, there is presented (Table II) a list of 

 substances which give evidence of being amphisymmetric, 

 with their respective structural and latent symmetry 

 classes, as far as these are at present known. Where a 

 group of compounds shows similar relations throughout, 

 only one typical member is given, but the number of 

 members included is indicated by numerals in parentheses 

 after the mineral name. The order is in general that of 

 increasing complexity of the compounds and of decreas- 

 ing symmetry. Class names and numbers are modified 

 from Groth's "Physikalische Krystallographie. " 



Table II. Amphisymmetric Substances. 



Mineral name. 

 Diamond 

 Alabandite 

 Sodalite gr.(4) 

 Bromyrite 

 Kalinitegr.(40) 

 Halite gr.( 15) 

 Cuprite 

 Xitrobarite gr. (3) 



Langbeinite 

 Cobaltite gr.(5) 

 ]S"ephelitegr.(3) 

 Spangolite 

 Scheelite gr.(4) 

 Scapolite gr.(5) 

 Eutile 

 Phosgenite 



Wulfenite 

 Stephanite 

 Manganite 

 Aragonite gr.(4) 

 Sulfur 



Diopside 



Formula. 

 C 



MnS 



Na 4 Al 3 aSi 3 12 

 AgBr 



KA1(S0 4 ),.12H,0 

 NaCl 

 Cu,0 



Ba(N0 3 ), 

 NaSrAs0 4 .9H,0 

 K 2 Mg 2 (S0 4 ) 3 

 CoSAs 

 NaAlSi0 4 

 Cu g A1C1SO 10 .9H,O 

 CaW0 4 



Na 4 Ca 4 Al 9 ClSi 15 49= 

 TiTi0 4 

 Pb,Cl,C0 3 

 NiS0 4 .6H 2 

 KH,P0 4 gr. 

 PbMo0 4 

 Ag 5 SbS 4 

 MnOOH 

 CaC0 3 

 S 



AgN0 3 



H,Na,P,0 6 .6H,0 

 MgCaSiA 

 LLS0 4 .H,0 

 Sr(C,H,6,)(N0 3 ). 

 liH 2 



Symmetry Classes. 

 Structural. Latent. 



Cubic holosym. (32) 

 Cubic holosym. 

 Cubic holosym. 

 Cubic holosym. 

 Cubic holosym. 

 Cubic holosym. 

 Cubic holosym. 

 Cubic hextetrah.(31) 

 Cubic hextetrah. 

 Cubic hextetrah. 

 Cubic diploidal( 30) 

 Hexag. holo.(29) 

 Hexag. holo. 

 Tetragonal holo. (15) 

 Tetragonal holo. 

 Tetragonal holo. 

 Tetragonal holo. 

 Tetragonal holo. 

 Tetragonal holo. 

 Tetragonal holo. 

 Orthorh.holo.(8) 

 Orthorh. holo. 

 Orthorh. holo. 

 Orthorh. holo. 

 Orthorh. holo. 

 Monoclinic holo. (5) 

 Monoclinic holo. 

 Monoclinic holo. 



Triclinicholo.(2) 



C. hextetrah. (31) 

 C. hextetrah. 

 C. hextetrah. 

 C. diploidal(30) 

 C. diploidal 

 C. gyroidal(29) 6 

 C. gyroidal(29) 8 

 C. tetartoidal(28) 

 C. tetartoidal 

 C. tetartoidal 

 C. tetartoidal 

 Hex. pyr.(23) 

 Ditrig. pyr.(20) 

 Tetr. bipyr.(13) 

 Tetr. trapez. 

 Tetr. trapez.(12) 

 Tetr. trapez. 

 Tetr. trapez. 

 Tetr. scaleno(ll) 

 Tetr.pyr.(lO) 

 Orth.pyr.(7) 

 Orth. pyr. 

 Orth. pyr. 

 Orth. bisphen.(6) 

 Orth. bisphen. 

 Monocl. domat. (4) 

 Monocl. domat. 

 Monocl. sphen.(3) 



Asymmetric (1) 



6 It is noteworthy that since all of the supposedly cubic-gyroidal substances 

 are amphisymmetric, no crystal is known which structurally belongs to this 

 class. 



