text: Basic mineralizers such as NaOH or NaCO are used in the hydrothermal growth of quartz crystals. The precursor or nutrient is crushed silica and a solvent. Typical containers are made of air-tight steel cylinders called autoclaves that can withstand high temperature and pressure. In the case of quartz crystals, the container is heated at 300 °C (which produces a pressure of 140 MPA). Without the mineralizer, higher temperatures are required to solubilize silica. Hydroxides and carbonates make silica more soluble by forming water-soluble sodium silicates. Simplified equations can be represented as in the equation below 
  :SiO + 2 NaOH → NaSiO + HO
  :SiO + NaCO → NaSiO + CO
  Anhydrous sodium silicate is a chain polymeric anion composed of corner shared SiO tetrahedra. Hydrates form with the formula NaSiO•nHO which contain the discrete, approximately tetrahedral anion SiO(OH) with waters of hydration. In three-dimensional silica glass, the addition of sodium ions causes oxygen ions formed a bridge, these oxygen ions possess an effective negative charge. The positively charged sodium ions provide partly covalent and partly ionic structure. As the concentration of Na increases, ionically bound material link and eventually form a network of continuous channels. Once silica is solubilized, components in the nutrient are transferred to the seed crystal, which is held at a cooler temperature than the nutrient, resulting in a high purity quartz crystal.