Practices such as astrology or crystal healing can be defined as pseudoscience. Against pseudoscience, one of the major responsibilities of science education must be to develop science-literate individuals who are able to understand what science is, how science is undertaken, how scientific knowledge is constructed, and how it is justified, then they will be able to determine whether a claim is valid and be alert to practices which fall outside the realms of science, especially those in the area of pseudoscience. For this reason, the ability of recognizing flawed process and claims of pseudoscience is referred to one of the crucial parts of science literacy. The present study aimed to uncover middle school students' understanding of the inherent aim of pseudoscientists and pseudoscientific applications related to crystals and to reveal their judgments and justifications regarding the effectiveness and scientific basis of these applications. The present study was qualitative in nature. The results of the study showed that the students were very gullible about the aim, effectiveness, and scientific basis of pseudoscientific practices and in particular the use of crystals. Furthermore, similar to pseudoscientists, the students generally used weak reasoning to evaluate the presented claims and research designs about crystals and crystal healing.