The term High Purity Quartz, also known as HPQ, is reserved for quartz material that satisfies exacting quality requirements for use in several critical applications in the solar photovoltaic, semiconductor, optical fibre, specialist glassware and optics industries. HPQ feedstock (HPQF) deposits can be defined as naturally occurring quartz in economically viable quantities that are amenable to beneficiation and purification to meet those quality requirements.  The main quality determinants include a very low level of impurities, an application-dependent particle size distribution, and melting behaviour that are acceptable for downstream manufacturers. However, and most importantly, commercially the term HPQ is reserved for processed quartz material that satisfies those exacting standards. None of the products mentioned above can be manufactured without a reliable supply of consistent quality HPQ and HPQF. The rapidly growing solar PV market is predicted to require significant new sources of supply over at least the remainder of this decade.

The processing required to produce HPQ depends on the amount and type of impurities present in the HPQ Feedstock and may include crushing, screening, floatation, acid-washes, magnetic separation and/or other physical, chemical, and thermal techniques.