Signs and symptoms of an ACL injury usually include: 1  A loud pop or a popping sensation in the knee. 2  Severe pain and inability to continue activity. 3  Swelling that begins within a few hours.  Loss of range of 1  motion. A feeling of instability or giving way with weight bearing.
Subsequently Emerald City has occasionally been used as an unofficial nickname for the city of Sydney. The city of Seattle, Washington, in the United States uses The Emerald City as its official nickname, on account of how green it is in that region of the world.
Emeralds are green for the same reason as rubies are red. The ruby is a regular crystal of corundum containing chromium as an impurity. The emerald is a regular crystal of beryl that also contains chromium as an impurity. Beryl is the term given to beryllium aluminum silicate (Be2Al2Si6Ol8). In rubies an aluminum atom in the beryl lattice is replaced by a chromium atom.