Petrified wood belongs to the group of florogenic jewelry and ornamental materials. It is widely used for the manufacture of various types of products. The paper presents first results of a detailed gemological and mineral-geochemical study of the petrified wood of jewelry and ornamental quality from Sakhalin Island. The petrified wood is associated with the Santonian and Campanian deposits of the Late Cretaceous age. According to the mineral composition and decorative and technological characteristics, two types of petrified wood can be distinguished. The first type of petrified wood is characterized by almost complete replacement of the wood original organic compounds mainly by quartz and, to a lesser extent, by calcite with inclusions of pyrite, dolomite, microcline, and kaolinite. In the second type, the role of calcite increases significantly, while the quartz content decreases. Fragments of petrified wood are of large size and good decorative, technological, and ecological characteristics. It can be collected in the rivers with other types of jewelry and ornamental materials at little costs and without destroying the environment.