Knowledge Column

In order to let more people know about polishing and grinding, Honway update the knowledge column from time to time.

Moon stone

A gemstone that radiates moonlight-like sheen — Moonstone

Gemstones / By

Moonstone is a renowned phenomenon gemstone. In addition to the basic 4Cs(carat, color, clarity, cut), the optical effect is a crucial consideration. High-quality moonstone is semi-transparent, while lower quality ones appear milky and turbid with less adularescence. The best moonstone display a vivid blue sheen when viewed from the front; if this effect is only seen in parts, the gemstone’s value decreases. Moreover, moonstones exhibiting both cat’s eye effect and blue sheen are extremely rare and valuable!

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A gemstone that glows at night — Fluorite

Gemstones / By

Fluorite comes in various colors due to its exposure to different minerals during its formation process. Its unique color change and fluorescence are also caused by trace amounts of transitional or rare earth elements. There are two main directions for selecting fluorite for collection: one is choosing faceted gemstones, and the other is selecting phenomena stones such as fluorescence, phosphorescence, color change, etc. Fluorite plays a significant role in industries such as metallurgy, optics, and electronics, special lenses in laboratories are also made from fluorite, which have excellent dispersion resistance.

符山石

The Versatile Crystal Gemstone — Idocrase

Gemstones / By

Idocrase is a gemstone with a highly variable crystal form, resembling other minerals such as tourmaline, fluorite, zircon, and garnet. This resemblance led to its name “Idocrase,” meaning “mixed form” in Greek. Another name for the gemstone, Vesuvianite, comes from its discovery near Mount Vesuvius, Italy. Idocrase is quite durable and does not require special care, but it should be protected from prolonged exposure to sunlight (UV rays) to avoid fading.

Diopside

Gem in the Ceramics Industry—Diopside

Gemstones / By

Diopside possesses a high birefringence, so when viewed through its faceted surfaces, you can see a clear double image of the underlying facet edges. In the gemstone world, it is considered a relatively affordable green gemstone with a high cost-performance ratio. In industry, diopside is a commonly used raw material in ceramics, stabilizing the firing process and improving the quality of the ceramic products.

硬水鋁石

The Color-Changing Gemstone—Diaspore

Gemstones / By

硬水鋁石（Diaspore），英文名來自希臘文，意指「分散」，因其加熱後會爆裂四散。這種水合鋁氧化物礦物屬斜方晶系，與針鐵礦為異質同構礦物，晶體呈扁平狀，聚晶呈片狀或鱗狀晶簇，解理發達，破裂面常有珍珠光澤。硬水鋁石通常為無色、灰色、淡黃色，稀有紫色也可見。觀賞價值高的變色硬水鋁石，產自土耳其，商業上稱為「舒坦石」（Zultanite），其變色效應不亞於亞歷山大石，變色效果包括綠色、粉紅色、黃色和紫色，變色效應強的大克拉數標本極為稀有，難以估價。

在工業上，硬水鋁石廣泛存在於鋁土礦、紅土和某些岩石中，可用作耐火材料和鋁的提煉。硬水鋁石硬度高，不易刮擦，但因解理發達，需避免碰撞和接觸刺激性化學物質，如家用清潔劑和香水，這些可能會損害寶石。

Charoite

Gemstone Like Twining Dragons — Charoite

Gemstones / By

Charoite, a rare purple silicate mineral, is characterized by its radiating fibrous metamorphic structure, which resembles a group of entwined dragons, hence earning it the commercial name Purple Dragon Crystal. The other name, Charoite, is derived from its discovery site along the Chara River in Russia. In terms of color, the only gemstone similar to it is Sugilite, but the two can be differentiated by their crystal structures. A gemstone with a similar fibrous structure is Seraphinite, though its composition is entirely different from that of Charoite.

Cleavage introduction diagram

Why is “cleavage” important in design?

Science Classroom / By

Cleavage refers to the property where a crystallized mineral breaks along weaker planes within the crystal structure under external force, forming smooth surfaces. In the gemstone industry, the cleavage characteristic is utilized by striking along the cleavage plane before cutting and polishing. Cleavage is classified into five grades based on the degree of perfection: perfect cleavage, good cleavage, fair cleavage, poor cleavage, and no cleavage. Cleavage is not only a critical factor in gemstone design but also serves as an important indicator in gemstone identification. Cleavage is an inherent property of gemstones, and even perfectly crystallized diamonds have cleavage planes.

磷灰石

The “Deceptive” Gemstone—Apatite

Gemstones / By

Apatite, whose name is derived from the Greek word meaning “deception,” is so named because its color and luster often resemble other gemstones. Apatite is a group of calcium phosphate minerals that contain chlorine or fluorine, with the main types being fluorapatite and chlorapatite. It comes in a variety of colors, including colorless, yellow, blue, purple, green, brown, and white, and may exhibit phosphorescence and strong pleochroism. Apatite is found in igneous, metamorphic, and sedimentary rocks, with gem-quality apatite mainly coming from pegmatites and alluvial deposits. Despite its relatively low hardness, making it less favored by jewelers, apatite is an important industrial mineral for extracting phosphorus, which is widely used in the medical, chemical, and other industries. When selecting apatite gemstones, flawless and brightly colored stones are the most desirable, especially those with a cat’s eye effect. While apatite is resistant to impact, it is susceptible to damage from acids, so proper care must be taken to avoid exposure to acidic substances.

賽黃晶

Rare gemstone variety – Danburite

Gemstones / By

Danburite is a kind of rare gem, the English scientific name comes from its discover location—Danbury, Connecticut, USA, the Chinese name is derived from its appearance, which is similar to topaz. It’s primarily found in pegmatite and metamorphosed carbonate rocks that are rich in cryogenic hydrothermal fluids, coexist with plagioclase and orthoclase in dolostone. Danburite can be found in colors ranging from colorless, light yellow, brown, to the rarer pink and purple. Commercially, the appearance and index of refractive of danburite are both similar to those of topaz, but danburite can be identified by its low specific gravity, fluorescence and low birefringence index. Most danburite appear gray and opaque, with gem-quality transparency being extremely rare, but even so most enthusiasts still value its natural appearance and regard it as collection. Danburite has high hardness and toughness, doesn’t require special maintenance in both collection and wear, makes it relatively easy to care.

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