Final answer:
The minerals from hardest to softest are quartz, topaz, apatite, and calcite, according to the Mohs scale of hardness. Quartz (hardness 7) and topaz (hardness 8) are significantly harder than apatite (hardness 5) and calcite (hardness 3). This ranking is essential for mineral identification and practical applications.
Step-by-step explanation:
The hardness of minerals is compared using the Mohs scale of mineral hardness. According to the Mohs scale, the minerals rank from hardest to softest as follows: quartz, topaz, apatite, and then calcite.
Quartz, with a Mohs hardness of 7, is one of the most common and hardest minerals among those listed. It does not only form beautiful crystals such as amethyst but is also very durable. Following quartz, topaz has an impressive hardness of 8, making it harder than most substances it would encounter in nature. Apatite, which is found in bones and teeth, has a notable hardness of 5, strong enough for the biological functions it serves. Lastly, calcite's hardness is only 3, which is relatively soft compared to many other minerals. Calcite's softness relative to its counterparts does not hinder its widespread presence, including its use in the structure of sea urchin teeth, where an increased concentration of magnesium provides required hardness.
Understanding the hardness of minerals is crucial, not only for identifying them but also for their various applications in different fields, including jewelry, manufacturing, and construction.