Chalcedony to as prase. However, the term prase is also used to describe green quartz, and to a certain extent is a color-descriptor, rather than a rigorously defined mineral variety.) Blue-colored chalcedony is sometimes referred to as "blue chrysoprase" if the color is sufficiently rich, though it derives its color from the presence of copper and is largely unrelated to nickel-bearing chrysoprase. Heliotrope is a green variety of chalcedony, containing red inclusions of iron oxide that resemble drops of blood, giving heliotrope its alternative name of bloodstone. In a similar variety, the spots are yellow instead, known as plasma. Moss agate
Aluminium alloy inclusions (AlN), iron oxides (FeO), manganese oxides (MnO), fluorides (NaAlF, NaF, CaF, …), aluminium borides (AlB, AlB), borocarbides (AlCB). Bone ash (Ca(PO)) sometimes added to patch cracks in the trough can be found as inclusions in the melt. Several methods exist to measure the inclusion content in liquid aluminium. The most common methods are PoDFA, Prefil, K-Mold and LiMCA. Measuring the inclusions is of great help to understand the impact of furnace preparation, alloying practice, feedstock mix, settling time, and similar parameters on melt cleanliness. The PoDFA method provides information on the composition and concentration of the inclusions in molten aluminum.