Nearly all of the proppant available on the market today can be classified into one of three tiers--sand, resin-coated sand, or ceramic. The products contained in these three tiers have served the industry well and have typically covered the broad spectrum of applications required by completions engineers. However, with the development of deeper reservoirs and the ongoing look at geothermal and steamflood applications, there now exists a gap in proppant technology. No conventional proppant can provide sufficient conductivity at the 20,000-psi (and higher) closure stresses anticipated in the Lower Tertiary formations in the deep Gulf of Mexico. Similarly, no conventional proppant can adequately withstand the harsh chemical conditions in many geothermal and steamflood applications. The industry has begun to address this gap in performance with the development of higher-strength proppants. One such proppant has been developed and commercialized to meet these challenges. It achieves twice the baseline conductivity of any conventional proppant at these high stresses, and should also provide additional advantages because of increased durability. This paper will review the step-change advancements achieved by this new proppant, including improvements in both raw materials and manufacturing processes. It will present properties never seen before in regard to proppant shape, sizing, and strength. Extensive laboratory testing has been completed and will be presented to demonstrate the superior performance of the proppant in harsh conditions. The paper will also outline the expected applications for this product, including areas in which increased production rates, superior estimated ultimate recovery, lower erosivity, and reduced equipment wear are primary concerns. Field applications are under way to properly assess the implications of these findings. This paper should be beneficial to all completions engineers and production technologists currently working in regions with high-stress applications (= 14,000 psi) or other harsh conditions such as those of steamflooding and geothermal applications.