Apple Watch What's So Great About Sapphire?

                        From  alerting   you  to  an  incoming  call  to  monitoring  your  heart rate, t he newly  unveiled  Apple  Watch  is  being  promoted  as  the  next  great  high-tech  tool  for gadget  lovers  and  fitness  fans.  But  two  of  the  smartwatch's  most  practical  features   its sapphire  screen  and  lenses  aren't  all  that technologically  advanced.

                      Not  to  be  confused  with  the  sapphire  gemstones  you  might  find  at  a  jewelry shop,  the  synthetic  sapphire  used  on  the  Apple Watch  is  a  very  basic  substance   the crystalized  form  of  aluminum  oxide.

                    "If  you  take  aluminum  metal  and  allow  it  to  sit  outside,  it  starts  to  oxidize.   This   material,   when   grown   as   a   single   crystal,   is  intrinsically   transparent, " said           Harry Tuller,    a  professor  of  ceramics  and  electronic  materials  at  the  Massachusetts Institute  of  Technology (MIT). [Fantasy Fitness Tracker: 8 Absolutely Must-Have Features                               Its  crystal-clear  transparency  makes  sapphire  ideal  for  display  screens.  The same  can  be  said  about  its  hardness,  which,  Tuller  said,  is  second  only  to  diamond. When  it  comes  to  sapphire's  use  in  gadgets,  hardness  is  definitely  a   good    thing, because  the  harder  a  material  is,  the  more  difficult  it  is  to  scratch  or  crack,  Tuller  told Live  Science.

                   Sapphire's  hardness  allegedly  means  that  Apple  Watch  wearers  can  drop  the watch  and  bump  their  wrists  against  things  quite  a  bit  without  severely  damaging   the device.  And  that  would  likely  not  be  the  case  if  the  smartwatch's  display  were  made of  Gorilla Glass,   the  material  developed  by  New  York-based   manufacturer  Corning  that has  been  used  in  the  display  screens  for  most  of  Apple's  other devices.

                        "The  attractive  thing  about  glass  is  that  it's  transparent  and  inexpensive," Tuller  told  Live  Science.  " But  it's  much,  much  less  hard  than  sapphire."

                           Gorilla  Glass  isn't  an  inferior  product,  however.  The  chemically infused  glass  is  much  more  durable  than  normal  glass,  and  as  iPhone users  may  have noticed,  it  stands  up  fairly  well  to  scratching  and  even  hard  knocks.  However,  compared with  sapphire,  Gorilla  Glass  isn't  all  that  durable,  Tuller said.

                             Sapphire  is  more  expensive  to  make  than  chemically  treated  glass,  but for  Apple,  the  material's  price  seems  to  be  something  of  a  selling  point,   according to Tuller,  who  added  that  sapphire  has  long  been  used  in  the  face  coverings  for  expensive watches.

                            "Apple  always  wants  something  more  elegant,  more  attractive,  more valuable,  " Tuller said. "[The Apple Watch] is  not  just  a  throwaway  thing,  and  this  is obviously  one  way   of  distinguishing  themselves  from  their  competitors."

                             In  addition  to  its  sapphire  display,  Apple  Watch's  sensors  will  feature lenses  made  of  sapphire,  the  company  announced  this  week.  These  sensors  are  located  on  the  backside  of  the  watch  and  will  reportedly  use  infrared  and  visible-light LEDs  to  detect the wearer's heart rate.

                               "Sapphire  is  very  transparent  over  a  very  wide  wavelength  range,  so  it's  going  to  be  excellent  at  transmitting  any  signals  that  come  from  your  body,  like infrared  heat,"  Tuller  said.  Transmitting  these  types  of  signals  through  sapphire,  rather than  traditional  glass,  will  most  likely  be  clearer,  though Tuller  admits  the  difference  is  probably  minuscule.