﻿126 
  T. 
  H. 
  Lee 
  — 
  Two 
  New 
  Zircon 
  Minerals. 
  

  

  Art. 
  VI. 
  — 
  Two 
  New 
  Zircon 
  Minerals 
  — 
  Orvillite 
  and 
  

   Oliveiraite; 
  by 
  T. 
  H. 
  Lee, 
  F.C.S., 
  Lond., 
  N. 
  Am. 
  

   C. 
  Soc. 
  

  

  [Translated 
  by 
  J. 
  C. 
  Branner 
  from 
  the 
  Kevista 
  da 
  Sociedade 
  Brasileira 
  de 
  

   Sciencias, 
  No. 
  1, 
  Eio 
  de 
  Janeiro, 
  1917, 
  pp. 
  31-38.] 
  

  

  I. 
  Orvillite. 
  

  

  Year 
  before 
  last 
  there 
  came 
  to 
  the 
  Servigo 
  Geologico 
  e 
  

   Mineralogico 
  do 
  Brazil 
  a 
  number 
  of 
  specimens 
  of 
  a 
  

   zirconif 
  erous 
  rock 
  from 
  the 
  region 
  of 
  Caldas, 
  in 
  the 
  State 
  

   of 
  Minas 
  Giraes. 
  Several 
  of 
  them 
  were 
  almost 
  entirely 
  

   of 
  the 
  oxide 
  of 
  zirconium 
  known 
  as 
  baddeleyite 
  (brazil- 
  

   ite 
  of 
  Hussak), 
  and 
  some 
  of 
  them 
  contained 
  92% 
  of 
  the 
  

   oxide 
  of 
  zirconium. 
  

  

  When 
  Orville 
  A. 
  Derby, 
  the 
  lamented 
  director 
  of 
  the 
  

   survey, 
  received 
  this 
  material 
  he 
  began 
  a 
  study 
  of 
  it 
  with 
  

   a 
  view 
  to 
  proposing 
  the 
  name 
  "caldasite" 
  for 
  the 
  rock 
  

   itself, 
  so 
  that 
  the 
  name 
  baddeleyite 
  would 
  be 
  restricted 
  

   to 
  the 
  crystalline 
  oxide 
  of 
  zirconium, 
  and 
  thus 
  prevent- 
  

   ing 
  the 
  use 
  of 
  the 
  name 
  of 
  the 
  mineral 
  for 
  that 
  of 
  the 
  

   rock. 
  And 
  as 
  it 
  is 
  typical 
  of 
  the 
  region 
  of 
  Caldas, 
  its 
  

   origin 
  would 
  thus 
  be 
  indicated. 
  

  

  Among 
  the 
  many 
  varieties 
  of 
  this 
  rock 
  are 
  some 
  that 
  

   have 
  cavities 
  filled 
  with 
  small 
  crystals 
  of 
  silicate 
  of 
  zir- 
  

   conium 
  (zirconite). 
  By 
  making 
  analyses 
  of 
  this 
  mate- 
  

   rial 
  I 
  have 
  verified 
  the 
  existence 
  of 
  the 
  new 
  silicate 
  here 
  

   described. 
  It 
  is 
  of 
  an 
  unusually 
  simple 
  composition 
  for 
  

   one 
  of 
  the 
  rare 
  earths. 
  

  

  The 
  first 
  analysis 
  made 
  gave 
  the 
  following 
  results, 
  

   which 
  are 
  the 
  average 
  of 
  two 
  closely 
  agreeing 
  deter- 
  

   minations 
  : 
  

  

  Combined 
  water 
  1-56 
  

  

  Alumina 
  0-15 
  

  

  Zirconia 
  71-88 
  

  

  Titanic 
  acid 
  ■ 
  0.62 
  

  

  Ferrous 
  oxide 
  0-43 
  

  

  Silica 
  25-31 
  

  

  99-95 
  

  

  These 
  results 
  show 
  that 
  the 
  material 
  corresponds, 
  in 
  

   molecular 
  composition, 
  to 
  a 
  mixture 
  of 
  two 
  or 
  more 
  

   compounds. 
  

  

  