(-Sqrt[(3/5)] <= x < Sqrt[5/
    3] && ((z == (-35 + 7 Sqrt[15] x)/(8 Sqrt[21]) && 
       y == (-35 + 7 Sqrt[15] x - 10 Sqrt[21] z)/(
        14 Sqrt[15])) || ((-35 + 7 Sqrt[15] x)/(8 Sqrt[21]) < z <= 
        0 && (-35 + 7 Sqrt[15] x - 10 Sqrt[21] z)/(14 Sqrt[15]) <= 
        y <= (105 - 21 Sqrt[15] x + 20 Sqrt[21] z)/(
        28 Sqrt[15])) || (0 < z < (35 - 7 Sqrt[15] x)/(
        12 Sqrt[21]) && (-35 + 7 Sqrt[15] x + 10 Sqrt[21] z)/(
        14 Sqrt[15]) <= y <= (105 - 21 Sqrt[15] x - 40 Sqrt[21] z)/(
        28 Sqrt[15])) || (z == (35 - 7 Sqrt[15] x)/(12 Sqrt[21]) && 
       y == (-35 + 7 Sqrt[15] x + 10 Sqrt[21] z)/(
        14 Sqrt[15])))) || (x == Sqrt[5/3] && z == 0 && y == 0)