﻿JOURNAL 
  

  

  OF 
  THE 
  

  

  WASHINGTON 
  ACADEMY 
  OF 
  SCIENCES 
  

  

  Vol. 
  12 
  October 
  19, 
  1922 
  No. 
  17 
  

  

  MINERALOGY. 
  — 
  A 
  worked 
  jade 
  pebble 
  from 
  Copan.^ 
  H. 
  vS. 
  Wash- 
  

   ington, 
  Geophysical 
  Laboratory, 
  Carnegie 
  Institution 
  of 
  Wash- 
  

   ington. 
  

  

  During 
  his 
  excavations 
  at 
  the 
  ancient 
  Maya 
  city 
  of 
  Copan, 
  Hon- 
  

   duras, 
  in 
  1919, 
  Dr. 
  Sylvanus 
  G. 
  Morley 
  found 
  a 
  fiat 
  pebble 
  of 
  jade> 
  

   (sawn 
  in 
  two 
  and 
  perforated), 
  on 
  the 
  platform 
  of 
  Stela 
  7.'- 
  (Fig. 
  1.) 
  

   The 
  material 
  of 
  this 
  pebble 
  seemed 
  to 
  be 
  of 
  such 
  interest, 
  and 
  its 
  

   pebble 
  form 
  argued 
  so 
  strongly 
  for 
  an 
  American 
  provenance, 
  that 
  

   I 
  expressed 
  a 
  desire 
  to 
  study 
  it. 
  I 
  am 
  deeply 
  indebted 
  to 
  Dr. 
  Morley 
  

   for 
  the 
  privilege 
  of 
  examining 
  the 
  object, 
  and 
  especially 
  for 
  his 
  liber- 
  

   ality 
  in 
  permitting 
  me 
  to 
  remove 
  a 
  few 
  grams 
  for 
  the 
  chemical 
  and 
  

   microscopical 
  study. 
  It 
  is 
  gratifying 
  to 
  know 
  that 
  the 
  mutilation 
  

   has 
  yielded 
  some 
  results 
  of 
  interest 
  in 
  connection 
  with 
  the 
  study 
  of 
  

   American 
  jades. 
  

  

  The 
  pebble 
  has 
  had 
  a 
  wide 
  cylindrical 
  perforation 
  bored 
  into 
  it 
  

   from 
  each 
  flat 
  side, 
  penetrating 
  almost 
  to 
  the 
  center 
  and 
  tapering 
  

   slightly 
  inward 
  ; 
  it 
  was 
  then 
  sawn 
  in 
  two 
  equatorially 
  down 
  the 
  center 
  

   about 
  half 
  way 
  between 
  the 
  two 
  flat 
  sides, 
  thus 
  freeing 
  the 
  cylindrical 
  

   cores 
  of 
  the 
  perforations, 
  which 
  (as 
  Morley 
  states) 
  were 
  probably 
  

   used 
  for 
  making 
  ear 
  ornaments, 
  either 
  disks 
  or 
  plugs. 
  ^ 
  The 
  width 
  

   of 
  the 
  equatorial 
  cut 
  was 
  about 
  5 
  mm. 
  

  

  With 
  this 
  pebble 
  was 
  found 
  a 
  finely 
  worked 
  and 
  highly 
  polished 
  

   deep 
  green 
  pendant, 
  7.5 
  cm. 
  high, 
  representing 
  a 
  human 
  figure, 
  with 
  

   the 
  arms 
  crossed 
  over 
  the 
  breast; 
  this 
  figure 
  was 
  intended 
  to 
  hang 
  

   with 
  the 
  side 
  outward. 
  The 
  weight 
  of 
  this 
  is 
  87.8300 
  grams, 
  and 
  I 
  

   found 
  its 
  specific 
  gravity 
  to 
  be 
  3 
  .307 
  at 
  22°, 
  indicating 
  that 
  it 
  is 
  com- 
  

   posed 
  largely 
  of 
  jadeite, 
  with 
  but 
  little 
  of 
  the 
  diopside 
  and 
  albite 
  

  

  ' 
  Received 
  October 
  3, 
  1922. 
  

  

  - 
  S. 
  G. 
  Morley. 
  The 
  inscriptions 
  at 
  Copan. 
  Carnegie 
  Publ. 
  219: 
  105. 
  1920. 
  

  

  ' 
  Dr. 
  Morley 
  thinks 
  that 
  the 
  perforation 
  was 
  carried 
  through 
  from 
  side 
  to 
  side; 
  but 
  that 
  

   it 
  extended 
  only 
  partly 
  through 
  from 
  each 
  side 
  is 
  indicated 
  by 
  the 
  slight 
  traces 
  of 
  a 
  ridge 
  

   at 
  the 
  bottom 
  edge 
  of 
  each 
  perforation 
  extending 
  a 
  milUmeter 
  or 
  so 
  inward 
  around 
  the 
  edge. 
  

   The 
  saw 
  marks 
  show 
  that 
  the 
  sawing 
  was 
  done 
  in 
  various 
  directions 
  and 
  extended 
  down 
  to 
  

   the 
  ])erforation, 
  the 
  marks 
  being 
  tangent 
  to 
  this 
  circle. 
  

  

  387 
  

  

  