Glass Glass was a clear substance . Sand could be made into glass , and would eventually do so if left alone for long enough . ( TV : " The Sea of Death " , " The Caves of Androzani " ) Broken , it could cut deep through flesh ; Lady Casaubon stabbed Orlo with a piece of glass , and then shot him with a glass bullet . ( PROSE : " Martha in the Mirror " ) The term " glass " was also used to describe cups made of glass . The First Doctor once remarked that Marinus had " beautiful glasses " . ( TV : " The Velvet Web " ) The Eleventh Doctor also used a glass cup to listen to the other side of the crack in Amelia Pond ' s bedroom . ( TV : " The Eleventh Hour " ) " Glasses " also referred to spectacles , which had glass lenses . ( TV : " The Girl Who Waited " , " The Angels Take Manhattan " , et al . ) Manfred Grieg , who had been trapped in the Mortal Mirror , was cursed with a perpetual body of glass , and kept a glass diary . ( PROSE : " Martha in the Mirror " ) A Wanarian battle cruiser was capable of turning an area the size of Cardiff into glass . ( PROSE : " Pack Animals " ) Ian Chesterton once hypothesised that a crystal box was made of glass , although the First Doctor quickly dismissed his idea , saying that it must have been " more sophisticated than that . " ( TV : " World ' s End " ) Physical properties . Glass was described by Ian Chesterton as " hard , " ( TV : " The Executioners " ) and by Turlough as " smooth . " Norna stated that you could " see through glass . " ( TV : " Frontios " ) One ' s reflection could be seen on glass , as well . ( TV : " Day of the Moon " , et al . ) The Seventh Doctor once described crystalline material as " polished smooth as glass . " ( TV : " The Caves of Androzani " ) In order to prove to Grace Holloway that the Eye of Harmony was harming the molecular structure of Earth , the Eighth Doctor walked right through a glass door . ( TV : " Doctor Who " ) Uses . Due to glass ' sharpness , a beach on Marinus was lined with broken glass as a defence mechanism . ( TV : " The Sea of Death " ) Some buildings , such as the Shard ( TV : " The Bell of Saint John " ) and the Gherkin , ( TV : " The Christmas Invasion " ) were made almost entirely of glass . Clock faces were made of glass . ( TV : " The Girl in the Fireplace " ) At least one of the components of a reticular vector gauge was also made from glass . Mirror s were also made of glass . ( PROSE : " Martha in the Mirror " , TV : " The Family of Blood " ) The Exhalation was an entire planet made of glass . ( PROSE : " Heart of Glass " ) Art was also made from glass ; stained glass windows were often found in places such as church es . ( TV : " The End of Time " ) It was also popular in rich households , at least during the Victorian era . ( TV : " Ghost Light " ) Barbara Wright once claimed that people put " freaks " in glass cases and examined them with microscope s . ( TV : " Dangerous Journey " ) Glass windows were found at the front of shops so that the merchandise can be seen clearly from outside . Mannequin s sometimes stood behind those shop windows . ( TV : " Rose " ) In the 21st century , some shops had automated glass doors , that " know you ' re there " . As Ianto Jones began to explain , " there are wave - bouncing detectors which emit radio waves and then look for reflections . " ( TV : " Out of Time " ) A magnifying glass was a glass that produced a magnified image of an object . Sun rays sent through a magnifying glass could be used to burn things . ( TV : " The Power of the Daleks " , " The Unicorn and the Wasp " , AUDIO : " The Spectre of Lanyon Moor " ) In the 19th century , common illusions were made using " projection on glass " , according to Charles Dickens . ( TV : " The Unquiet Dead " ) Durability . Finitoglass was a type of glass known for its durability , and could stand the radiation of an X - tonic ray for several minutes . ( TV : " Midnight " ) Vinvocci glass was capable of containing at least 500 , 000 rads of radiation . ( TV : " The End of Time " ) The Fourth Doctor once used high - pitched screaming to shatter glass ; he claimed that he picked it up from Nellie Melba . ( TV : " The Power of Kroll " ) Glass is general was considered durable , and was used to protect valuables . Some form of glass case was used to protect the " Mona Lisa " in the Louvre , although a sonic knife was able to cut through the glass . ( TV : " City of Death " ) A bank vault was made with titanium and protected by laser - proof glass and destructor ray s . ( COMIC : " Time of the Cybermen " ) Glass was also used to " trap " people ; Bernice Summerfield was once trapped in a glass prison by the Fifth Axis . ( PROSE : " The Glass Prison " ) Pinehill Crest Hotel ' s doors , made of safety glass , could not be broken even with a fire extinguisher . ( AUDIO : " The Shadow of the Scourge " ) Despite glass ' s durability , when the Tenth Doctor fell through a glass ceiling , it shattered all around him . ( TV : " The End of Time " ) Anything heavy or strong , such as a Minotaur , could shatter glass . ( TV : " The God Complex " ) The Tenth Doctor once demanded a truck in order to break through glass , although he eventually did so with a horse instead . ( TV : " The Girl in the Fireplace " ) Judoon blaster s could shoot through glass without difficulty . ( TV : " Smith and Jones " ) Davros once claimed that " the tiny pressure on [ his ] thumb [ would be ] enough to break the glass . " ( TV : " Genesis of the Daleks " ) Extreme sonic wavelengths , such as those caused by two identical sonic device s being held together , such as the Tenth Doctor ' s sonic screwdriver and Miss Foster ' s sonic pen , could shatter glass . ( TV : " Partners in Crime " ) Sometimes , this could happen simply using one device , such as the sonic lipstick . ( TV : " The Day of the Clown " ) When a spaceship hit Earth ' s atmosphere , the glass in at least central London shattered . ( TV : " The Christmas Invasion " ) As a result of this , Elton Pope could not move because of the sharp glass on the floor . ( TV : " Love & Monsters " )