Quartz sand is wide-spread mineral in Latvia. Latvian quartz sand of Jurassic deposit „Zīles” was examined. Ltd „Terra projects” prospecting result shows that quartz sand layer thickness reaches the largest area in the eastern part of the sand deposit up to 14.5 to 19.2 m depth. Approximate amount of sand stock 423400 m3, including groundwater level below 282700 m3. Chemical analysis of the sand shows that over the studied depth has a high content of SiO2 - 96.32 .... 98.21% and low content of Fe2O3 up to 0.33%, corresponding to the quartz sand requirements. Dominating granulometric fraction is 0,250 to 0,125 mm (84.40 to 91.20%), the sand deposits can be applied to medium and fine fraction deposit. It was found that the analogy to the other deposits of Kurzeme regions Jurassic sand, the general crystalline phase is quartz, other crystalline phases are not detected. SEM microphotographs of sand at different depths of 2.1-19.2 m, shows a heterogeneous sand grain surface. A similar surface was observed in all Jurassic deposits of Kurzeme region. In particular, a heterogeneous surface of the sample in depth - up to 8 m has showed a high content of fine fraction (11.5%). Scalelike sediment on grain of sand is surface impurities, which are easily removed by washing. DTA heating and cooling curves at temperature 5710C indicate the quartz α ↔ β polymorphic transformation. The surface impurities not affect the temperature of polymorphic transformation. Fourier transform infrared spectra of the samples are observed in quartz crystal characteristic spectral variations, surface impurities do not affect the quartz structure. Initial investigation of Jurassic deposit "Zīles" showed that due to the chemical composition and granulometry the quartz sand is used industrially and therefore requires to more detailed study of sand structure and properties.