The word porphyry originates from the Greek porphyry, meaning purple, originally referred to as igneous rock. It was originally used as a purple-red rock with alkaline feldspars from Egypt. Some people think that it is synonymous with Xiuyan. Porphyry is a neutral, acidic, or alkaline igneous rock with a patchy structure (either intrusive or exhaled).

    They are usually distributed in a scattered pattern between the crystal-clear minerals called "matrixes," which are usually referred to as sphalerites and paleolithites with alkali feldspars as speckles, substrates as fine grains, or cryptocrystals. Porphyry is a igneous rock with a porphyritic structure that is relatively strong and can be used as a building material. Speckles generally consist of alkaline feldspar or quartz, and the matrix is fine or cryptocrystalline (vitreous).

    Natural porphyry is characterized by compact structure, hard texture, high compressive strength, low water absorption, excellent abrasion resistance, strong corrosion resistance, good frost resistance, and good durability and decorative properties. The quality of natural porphyry is determined by the mineral composition and structure. The fine granite has fine and uniform crystal grains, tight structure, high quartz content, and low content of mica, and does not contain impurities such as pyrite. The feldspar has bright luster and no signs of weathering.

    The density of natural porphyry is about 2.80g/cm3, the apparent density is 2600~2800kg/m3, the compressive strength is high, usually 120~250MPa; the porosity and water absorption rate are very small, and the water absorption rate is often 1% The following; coefficient of expansion (5.6 ~ 7.34) × 10-6 / °C, frost resistance reached 100 to 200 times; weathering, fine-grained porphyry used for more than 500 years, coarse-grained porphyry The service life is up to 100-200 years; it has high corrosion resistance to nitric acid and sulfuric acid, and can be used as acid-resistant lining of equipment; the surface of polished granite sheet is smooth, colorful, solid texture, gorgeous and solemn, decorative it is good.