When looking at an diamond I bought in 1990 under a loupe I saw a trigon on a star facet and a natural on a star facet on the opposite site of the diamond. Due to the angle of cutting on the crown does this mean that this diamond was not cut from an octahedron shaped crystal. What type of crystal would it have been cut from if you can tell. Also what is the angle on a octahedron crystal is it sixty degrees with cleavage being at 70 degrees or something.