Showing posts with label Calcite. Show all posts
Showing posts with label Calcite. Show all posts

Calcite

Alabaster perfume jars from the tomb of Tutankhamun, (d. 1323 BC)
Alabaster perfume jars from
the tomb of Tutankhamun,
(d. 1323 BC)
Egyptologists today correctly use the term calcite when  referring to lithic materials that were historically called travertine,  alabaster,  Egyptian  alabaster,  or  Oriental  alabaster.  Geologically, calcite is  a  mineral  composed  of  hexagonal  crystals  of  calcium  carbonate (CaCO,). As used by geologists, the term alabaster refers  to  a  fine-grained,  massive  variety  of  rock  gypsum,  consisting  largely  of the  mineral  gypsum  (hydrous calcium  sulfate,  CaSO,,  •  2H;0),  which  is  a  secondary  mineral  formed  by  the  hydration  of  anhydrite (CaSC^) in a zone of weathering. Ironically, alabastrites  was the original, ancient Greek and Latin name used for "Egyptian  travertine" (a limestone), but that had been forgotten when alabaster  acquired  its  modem  definition  in  the  1500s.  Another  term  sometimes used for Egyptian travertine is calcite-alabaster, which  is  both  inappropriate  and  self-contradictory.  Many Egyptologists now call travertine by the term calcite, to avoid confusion with the  well-known  and  very  different-looking  Italian  travertine,  from  Tivoli, Italy (the Romans' tivertino, the Latin word for "travertine").  From the Old Kingdom onward, the Egyptians called travertine ss,  but during the Old Kingdom it was also occasionally referred to as  biyt.

Egyptian travertine (calcite) occurs in two varieties:  (1) a nonbanded to faintly banded, tan to brownish-yellow, coarse- grained, translucent form; and (2) the strikingly banded form with  interlayering  of  the  first-mentioned  variety  with  a  white,  fine- grained,  opaque  form.  With  prolonged  exposure  to  sunlight,  the  brown  and  yellow  colors  become  white.  An  example  of  this  weathering phenomenon may be seen at the Mosque of Muhammad  Ali (built from 1824 to 1848 CE) in Cairo's Citadel. Both the interior  and  exterior  surfaces  of  this  building  were  clad  with  banded  travertine (calcite), but now the outside surface has become nearly  white whereas the inside surface is still brightly colored.

Travertine  (calcite)  occurs as  fracture-and-cavity  fillings  in  the  limestone deposits that border the Nile Valley between Esna in the  south and Cairo in the north, and nine ancient quarries are known  for this rock. The locations, from south to north, and the dates for  these sites are the following: one site near Wadi Asyut (New Kingdom);  four  sites  near  the  Tell  el-Amama  ruins  at  Hatnub  (Old  Kingdom through Roman period), both in and near Wadi el-Zebeida  (Middle and New Kingdoms), and in Wadi Barshawi (possibly Middle Kingdom); one site at el-Qawatir  near the city of el-Minya (possibly Old through New Kingdoms);  one site in Wadi Umm Argub near the Wadis Muwathil and Sannur  (Late  period);  one  site  in  Wadi  Araba  near  Wadi  Askhar  el-Qibli  (Roman); and one site in Wadi el-Garawi near the city of Helwan  (Old  Kingdom).  Banded  travertine  was  obtained  from  all  those  quarries,  but  the  nonbanded  variety  may  have  come  only  from  Hatnub.  (Hatnub  is  an  ancient  Egyptian  word  meaning  "golden  house," and it may have been applied to that quarry because of the  uniform golden-brown color of its rock.).

As  a  relatively  soft  mineral  (number  3  on  the  Mohs  Hardness  Scale), calcite is easily worked with bronze, copper, and other metal  or stone tools. Its translucency, pleasing colors, and ability to take a  fine polish made it a popular decorative stone in Egypt from early dynastic times onward. Because of the difficulty of obtaining large  pieces, it was mainly employed for small objects, such as statuettes,  shawabtis,  offering  tables,  vases,  bowls,  dishes,  canopic  jars,  and  unguent jars. The unguent jars are the alabastra of classical Greece,  originally  ceramic  and  only  later  carved  from  Egyptian  travertine  (calcite), hence the Greco-Roman name alabastrites for this rock.

Occasionally, calcite was used for paving stones and wall linings  in temples as, for example, in the fourth dynasty valley temple of  Khafre at Giza and the nineteenth dynasty sanctuary in the temple  of Ramesses II  at Abydos, respectively. Although large travertine  (calcite) objects are less common than small ones, many are known;  these  include  sarcophagi,  life-size  and  colossal  statues,  naoi,  embalming  beds,  whole  shrines,  and  other  objects.  One  mode  of  transport for such articles was shown in a detailed painting on the  wall of the twelfth dynasty tomb of Djehutihotpe (or Thuthotpe) at  Bersheh,  where  a  colossal  statue  of  that  nobleman  is  pulled  on  a  sledge by 172 men. Some notable examples of large objects are the  following:

(1) the sarcophagus of King Sety I from his tomb in the Valley of  the Kings at Thebes, now in Sir John Soane's Museum, London; (2)  two  huge  blocks  at  Kamak  temple  in  Luxor—one  a  Late  period  offering stand or kiosk foundation in the Great Court and the other,  possibly, a statue pedestal of uncertain age in the Central Court; (3)  the  colossal  statue  of  the  god  Sobek  with  the  eighteenth  dynasty King Amenhotep III (1382-1344) from Dahamsha, now in the Luxor Museum;  (4)  the  colossal  statue  of  King  Sety  I  from  Karnak  temple,  now  in  the  Egyptian  Museum,  Cairo;  and  (5)  two  bark  shrines,  one  by  the  eighteenth dynasty  kings  Amenhotep I/Thutmose I, and one by the twelfth dynasty king Senwosret I, now  in  the  open-air  museum  at  Karnak  temple.  Numerous  other  examples  may  be  found  in  Alfred  Lucas,  Ancient  Egyptian  Materials and Industries (1962).

Recent Pages:

Labels