Calcite vs Quartz
Calcite and quartz are highly abundant minerals on the earth surface. Both are present in all three types of rocks named as sedimentary, igneous and metamorphic rocks. Although they are highly available, they are valuable due to their significant differences in color, shape, properties, etc.
Calcite is a mineral, which contains calcium carbonate (CaCO3). This is an abundant mineral on the earth surface. Calcite can form rocks, and they may grow up to large sizes. They are found in all three types of rocks, which are sedimentary, igneous and metamorphic rocks. Different varieties of calcites can be formed due to variations in the distribution and environments. They can exist as colorless crystals, or sometimes can have white, pink, yellow or brownish colors. The crystals can be transparent, translucent or opaque, depending on the substances it has incorporated within when forming. The amount of calcium carbonate containing in the rock can vary. Sometimes, there are calcite minerals, which contain about 99% calcium carbonate. Calcite has unique optical properties. When a ray of light goes through a calcite mineral, it double reflects the light. Furthermore, calcite has fluorescence, phosphorescence, thermo luminescence and triboluminescence properties. Depending on the calcite variety, the extent of showing these properties may vary. Calcites react with acids and produce carbon dioxide gas. Especially in water, it becomes less soluble as the temperature increases, which allow calcite to precipitate and form more massive crystals. Calcites are relatively less hard, so they can be scratched by a fingernail. Calcite can be mainly found in Ohio, Illinois, New Jersey, Tennessee, and Kansas in USA, and Germany, Brazil, Mexico, England, Iceland, many African countries etc.
Quartz is the mineral which contains silicon dioxide (SiO2) mainly. Quartz has a unique crystalline structure with helix chains of silicon tetrahedrons. This is the second most abundant mineral in the earth surface and has a wide distribution. Quartz is a component of all three types of metamorphic, igneous and sedimentary rocks. Quartz can vary from one place to another by their color, transparency, the amount of silicon dioxide, size, constituents, etc. They can be colorless, pink, red, black, blue, orange, brown, yellow, purple colored. Some of the quartz minerals can be transparent, whereas come can be translucent. Citrine, amethyst, milky quartz, rock crystal, rose quartz, smoky quartz and prasiolite are some of the large crystal forming quartz types. Quartz is mostly found in Brazil, Mexico, Russia, etc. There are significant morphological differences in different quartz minerals; therefore, they are used as ornamental rocks. It is considered as a semiprecious stone and used in jewelry making. Further, quartz is used for ceramics and cements due to its high thermal and chemical stability.
What is the difference between Calcite and Quartz?
• Calcite mainly contains calcium carbonate and quartz mainly contains silicon dioxide.
• The hardness of quartz is higher than that of calcite. Quartz has Mohs hardness of 7, whereas calcite has Mohs hardness of 3. Therefore, calcite can be scratched by fingernail.
• Calcite can be easily identified because it dissolves in acids and produce carbon dioxide. Quartz does not dissolve in acids.
• Calcite has a perfect cleavage in three directions while quartz has a weak cleavage in three directions.