cube spar
Webster's Dictionary (GCIDE)
spar \spar\ (sp[aum]r), n. [AS. spaer in spaerst[=a]n chalkstone; akin to MHG. spar, G. sparkalk plaster.] (Min.) An old name for a nonmetallic mineral, usually cleavable and somewhat lustrous; as, calc spar, or calcite, fluor spar, etc. It was especially used in the case of the gangue minerals of a metalliferous vein. [1913 Webster]
Blue spar, Cube spar, etc. See under Blue, Cube, etc. [1913 Webster]
Cube \Cube\ (k[=u]b), n. [F. cube, L. cubus, fr. Gr. ???? a cube, a cubical die.]
1.(Geom.) A regular solid body, with six equal square sides. [1913 Webster]
2.(Math.) The product obtained by taking a number or quantity three times as a factor; as, 4x4=16, and 16x4=64, the cube of 4. [1913 Webster]
Cube ore (Min.), pharmacosiderite. It commonly crystallizes in cubes of a green color.
Cube root. (Math.), the number or quantity which, multiplied into itself, and then into the product, produces the given cube; thus, 3 is the cube root of 27, for 3x3x3 = 27.
Cube spar (Min.), anhydrite; anhydrous calcium sulphate. [1913 Webster]