How can you tell if both crops of crystals are your product? Why would additional solid precipitate in your filtrate?

Crops of the crystals are a part of the same crystal which might have different chemical structures leading to different colors.

Explanation:

Crops of the crystals are the parts of the crystals. And even being a part of the same crystal, the crops of the crystals can have different colors from the other crops of the crystal.

The color of crops of crystals are dictated by the chemical structure and their physical characteristic (crystalline or formless). The shape and the size of its crystalline structure, likewise the chance of polymorphism, may impact its shading.