A meneraloid is a type of mineral-like substance that shares some characteristics with minerals but does not fully meet the criteria to be classified as one. Meneraloids typically lack a definitive crystalline structure and may have an amorphous or non-crystalline form. Common examples include opal and obsidian, which exhibit mineral-like properties but do not possess a regular crystal lattice. These substances are often studied in geology and mineralogy for their unique properties and formations.