In order to let more people know about polishing and grinding, Honway update the knowledge column from time to time.
Introduction According to legend, the seven treasures of Buddhism include gold, silver, lapis lazuli, giant clam, agate, amber, and coral. In Western culture, red coral is believed to have transformed from the blood of Jesus. Whether viewed from a religious perspective or from Eastern and Western cultures, red coral is considered a rare and valuable …
Introduction The origin of the word “amber” in English is said to come from the Arabic word Anbar, meaning “gum.” The Spaniards referred to both the buried Arabic gum and amber as “amber.” In Chinese, the term “琥珀” is believed to have originated from the ancient belief that golden amber was the concentrated spirit and …
The word Apatite comes from Greek, meaning “deception,” because the mineral’s appearance can resemble that of emerald, sapphire, aquamarine, or amethyst, leading to confusion.
Apatite refers to a group of calcium phosphate minerals that contain either chlorine (Cl) or fluorine (F). The most common species is fluorapatite, followed by chlorapatite and hydroxylapatite. Apatite often contains rare earth elements like cerium (Ce), uranium (U), and thorium (Th), which can impart a wide range of colors, including colorless, yellow, blue, purple, green, brown, and white. Some apatite specimens exhibit phosphorescence, meaning they continue to glow after exposure to UV light. Additionally, apatite has strong pleochroism, where the color changes when viewed from different angles. However, due to its lower hardness, apatite is not as widely sought after in the jewelry market.
Apatite is found in igneous, metamorphic, and sedimentary rocks. In igneous rocks, apatite occurs mainly in pegmatites or hydrothermal veins, with gemstone-quality apatite typically sourced from pegmatitic granite. In sedimentary rocks, apatite forms through exogenic processes and contributes to the creation of phosphorite, a rock rich in phosphate minerals. In metamorphic rocks, apatite is generally found as an accessory mineral. Gem-quality apatite is most often extracted from alluvial deposits.
Commercial Value of Apatite
Apatite is easily confused with several common gemstones due to its appearance. Though it may be difficult to distinguish them with the naked eye, gemologists can easily identify apatite by examining its refractive index, birefringence, specific gravity, and clarity. However, it should be noted that apatite and tourmaline have similar refractive indices, requiring birefringence for differentiation. In the case of cabochon-cut stones, rather than faceted gems, distinguishing between the two becomes more challenging.
Industrially
About 90% of the phosphorus in nature comes from apatite, making apatite an important industrial mineral for extracting phosphorus. This element is widely used in various fields such as medical products, chemical products, textiles, clothing, inorganic products, and the removal of toxic substances. Its applications are quite extensive.
Ornamentally
Gem-quality cat’s eye apatite often contains parallel fibrous or tubular inclusions that easily create a chatoyancy effect in cabochon cuts. When selecting cat’s eye apatite, opt for visually flawless stones and vibrant colors like vivid blue-green (rainbow blue), which resembles Paraiba tourmaline, or intense green and royal blue. If these colors are combined with the cat’s eye effect, they are even more valuable and desirable.
Brownish-yellow cat’s eye apatite closely resembles the coveted cat’s eye chrysoberyl, and it is common to find apatite varieties with a similar “honey color,” which is highly sought after in chrysoberyl.
Though apatite lacks pronounced cleavage, making it relatively impact-resistant, its low hardness means it still requires careful handling to prevent scratching. Additionally, apatite is sensitive to acids, so it should not be exposed to acidic liquids or soaked in hot springs, as this could lead to potential dissolution.
Introduction Beryl represents an entire family of rare gemstones, with the most famous member being the green beryl known as “Emerald.” Among the many green gemstones, emerald is the most historically renowned, recognized across different cultures and eras. Even today, the term “green gemstone” is often synonymous with emerald. Emerald is the most significant member …
Introduction Ancient Indians believed that the red in rubies came from an internal, never-extinguishing flame burning within the gemstone. They also considered rubies to be the true “king of gems.” Unlike diamonds, rubies are not controlled by monopolistic companies like De Beers, which regulate supply and spend billions on marketing annually. Despite this, rubies maintain …
Introduction Diamonds are universally recognized as the king of all gemstones. With its cubic crystal structure, diamond possesses the highest hardness of any natural material on Earth, contributing to its immense value. Beyond its unparalleled hardness, the beauty and rarity of diamonds are further enhanced by their brilliance and vibrant rainbow-like appearance. In the current …
Introduction Jadeite Jade, known in Taiwan as “輝玉”, is commonly referred to as “硬玉” or “翡翠” in China. Because gemstone-quality jadeite mainly originates from Myanmar, it is also called “Burmese Jade” in the market. The term “硬玉” (Jadeite) originated from the belief that jadeite is generally harder than “軟玉” (Nephrite). However, Professor Tan Liping of …
Introduction In mineralogy, jade is categorized into nephrite and jadeite. Jade has historically been seen in the West as a medicinal stone believed to treat kidney ailments. In ancient China, however, jade was first used in sacrificial rituals, later becoming a symbol of rank and status cherished by nobles and scholars alike. In folklore, jade …
Introduction Lutetium is a relatively rare chemical element. French scientist Georges Urbain, Austrian mineralogist Carl Auer von Welsbach, and American chemist Charles James independently discovered lutetium in the mineral yttria in 1907. The name “lutetium” derives from the Latin “Lutetia,” the ancient name for Paris. Lutetium is scarce in nature, primarily found alongside other rare …
Introduction Promethium (Pm) is element number 61 in the periodic table, a rare, radioactive element. Promethium is artificially synthesized and cannot be directly found in nature. Its radioactivity and rarity make its study and acquisition challenging. In the 1930s, chemists produced some unstable radioactive elements through nuclear reactions. In 1945, scientists Charles D. Coryell and …
The radiant light of rare elements —— Promethium (Pm) Read More »
