in 9i try something like this ... for older versions there other motheds.

mag@mutation_mutation > set long 500000000000000
mag@mutation_mutation >  SELECT DBMS_METADATA.GET_DDL('INDEX',I.INDEX_NAME) from user_indexes I
  2   where INDEX_NAME='DOCTOR_DOCTORID_PK'
  3  /

DBMS_METADATA.GET_DDL('INDEX',I.INDEX_NAME)
--------------------------------------------------------------------------------

  CREATE UNIQUE INDEX "MAG"."DOCTOR_DOCTORID_PK" ON "MAG"."DOCTOR" ("DOCTORID",
"DOCTORDATE")
  PCTFREE 10 INITRANS 2 MAXTRANS 255
  STORAGE(INITIAL 65536 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645
  PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1 BUFFER_POOL DEFAULT)
  TABLESPACE "SYSTEM"