Learn Natural Gemstones, Minerals, Crystals Info, News, Tips, Researches

Luster is the property of minerals to reflect the light from the outer surface of the gemstones. These reflections of light are internal and make it look transparent in the case of facet stones. The light inside gemstones cannot be called luster. The properties of gemstones equated with luster are often defined as an outer image of the surface of a gemstone that makes it look brighter externally. Luster makes the mineral appear shiny or not shiny depending amount of light reflected from the gemstones. Gemstones and minerals can have a metallic appearance and sometimes they can be labeled as non-metallic luster. Scientifically, luster is defined as a shine in stones that is emitted when light is reflected from the surface of stones which is observable under the illumination.  How Luster is observed? Luster is usually observed under direct illumination of light. The light passes through the specimen and it reflects light to display the luster of minerals or gemstones. The examination of stones is to move the specimen through different wavelengths of light to observe at various angles to check the luster.  What are Types of Lusters in Stones?  There are different types of terms are used to define luster in minerals and gemstones. It includes the following terminologies that include Adamant, Vitreous, Silky, Greasy, etc.  There are two main types of Luster  Metallic (such as pyrite , hematite) Non Metallic (all gemstones) Nonmetallic Luster Many of the mineral specimens don't have any kind of metallic or sub-metallic luster. These minerals and their specimens are called "nonmetallic" luster. Many types of minerals have nonmetallic luster. The nonmetallic luster in gemstones and minerals can be characterized into the following types. Adamantine Sub Adamantine Vitreous  Sub Vitreous  Greasy Silky Pearly Resinous Waxy Dull Non-Metallic Luster Appearance Adamantine Sparkly Earthy Dull, clay-like Pearly Pearl-like Resinous Like resins, such as tree sap Silky Soft-looking with long fibers Vitreous Glassy Adamantine Adamantine is the ability of gemstones to shine or sparkle. For example, Diamond. Adamantine luster in minerals or gemstones has a high refractive index, which is between 1.9 and 2.6. Examples of adamantine luster are cerussite and anglesite.  Sub-Adamantine Sub-admantine has a luster that is relatively lighter the full adamantine-like diamonds. They have a close affinity to the adamantine and fall into category that is similar to the adamantine for example, Cubic Zircon.  Vitreous Some gemstones have a glass-like outer surface which includes tourmaline, Quartz, and topaz. Most gems have a vitreous or in other words, the glass-like surface is also called luster. It includes beryl, quartz, topaz, ruby, emerald, and other gemstones that have a refractive capacity that is between the range of 1.50 and 1.70 on its measurement scale. Sub-Vitreous Subvitreous is the ability of the gemstones that have a low reflection of light on the surface of gemstones. One the examples of sub- vitreous gemstones is fluorite. Greasy Some gems have a greasy surface that makes them look like oil-like or layer of a fat on its surface. Examples of greasy gemstones are serpentine, garnet, or peridot. The luster is not evenly distributed on the polished surface of gemstones but appears randomly or makes gemstones look flat in some areas on the surface. Silky The gemstones that have a silky luster are due to the fibrous material, for instance, gypsum and Malachite. The silky luster is also found in Ulexite or moonstone. The hemstone having silky luster often looks like fabric in its appearance and texture. The polished tiger's eye has a glassy luster that has a fibrous body. Pearly Some gemstones have a pearly outer surface that is similar to the pearl that is whitish in appearance. Some of the gemstones display iridescent play of colors on their surfaces that make them look different from other types of luster. Resinous Amber was found and preserved in prehistoric plants. The gemstone that falls into the category of resinous luster forms thick waxy substances on the surface of the gemstones for example, Sphalerite has a resinous luster. These gemstones are soft and have low refractive capacity like Amber and Opal. Waxy Some gemstones look like that has thick wax on the surface. The best example is turquoise and Opals. Jade is another mineral with a waxy luster. Waxy minerals are slightly transparent to translucent. The waxy minerals have small mineral extracts that disperse the light making it more waxy in its appearance. Most of these minerals will improve their appearance and bring out their color better with good polish. Dull Some of the gemstones have a dull luster as it is very low light. The dullness of luster has a fine surface like a grain. The dull luster is described as an "earthy" luster. The dull luster is non-reflective. The dull luster is a rough and porous surface that diverges the light instead of reflecting on minerals. Kaolinite, limonite, and hematite have a dull or earthy luster. Metallic The gemstones and minerals have metallic traces in them. Pyrite and Hematite are two examples that have ores of metal. Metallic gemstones are not used due to traces of metals in them.  The metallic minerals have the same color as the metals such as gold, silver, or copper. The metallic gemstone specimens are more reflective and don't lose their metallic luster. They appear to be opaque and have the same color as a metal.

There are many ways to test the stones such as hardness, fractures analysis, juding through crystal shapes and many others. Here we will discuss 10 popular testing methods one by one.

Cleavage is important while gemstone identification or we're dealing faceting the  rough gemstones. Learning about cleavage helps us in developing better understanding of the gemstones and crystals. Want to know more? Keep reading!

It is always difficult to recognize genuine stone from fake one. Before going deep into the study of gemstones, one must be aware of difference between imitation, synthetic stones and natural stones. Read more here...

Exploring Gemstone and Mineral Identification: A well explained study about Internal Observations of Inclusions   Understanding the complexities of Gemstone Identification through Internal Inclusions Gemstones and minerals have long been prized for their beauty and rarity, making them objects of fascination for scientists and enthusiasts alike. Today, we delve into the intricate world of internal observations of inclusions, shedding light on the characteristics that define these precious stones.   ### External Mineral Observation: The Foundation of Stone Quality   External observation methods, such as cut, polish, scratch, abrasion, and pits, play a crucial role in judging the quality of gemstones. However, our focus in this article lies on internal observation, a method intricately linked to the various types of inclusions within stones.   ### Unveiling the World of Inclusions   **What is Inclusion?** Inclusion, in the context of gemstones and minerals, refers to any material trapped within the stone during its formation under high pressure and temperature. This material can be another mineral, an element in various states (solid, liquid, gas), fractures, and more. The discovery of new inclusion types is an ongoing process, expanding the list of known inclusions in gemstones.   **Types of Inclusions: A Glimpse into the Hidden World** Researchers have identified several types of inclusions, each offering unique insights into the nature and authenticity of gemstones. Some notable examples include:   1. **Bubbles:** Typically found in gas bubbles. 2. **Needles:** Resembling needles or fibers, found in tourmaline, quartz, ruby, and sapphire. 3. **Silk:** Needle-like structures resembling silk feathers, commonly found in ruby and sapphire. 4. **Crystal:** Solid crystals within the mineral. 5. **Cleavage Fault:** Internal cracks, often found in Kunzite, diamonds, and topaz. 6. **Rain:** Dash-like lines. 7. **Color Zoning:** Uneven distribution of color in gemstones, frequently observed in corundum and amethyst. 8. **Dendritic:** Internal natural scenery resembling moss-agate. 9. **Halo or Disk:** Small fractures resulting from the growth of crystals inside the host stone. 10. **Twinning:** Parallel cracks, crucial for authenticating stones. 11. **Veils:** Small bubbles.   ### Identifying Inclusions: Imperfections that Validate Authenticity   While inclusions may be considered imperfections, they play a pivotal role in identifying the authenticity of gemstones. They act as markers, distinguishing natural stones from their synthetic counterparts. Although inclusions can sometimes weaken a stone, they can also enhance its beauty, as seen in minerals like petroleum quartz or pyrite inside lapis.   ### Types of Inclusions: Solid, Liquid, and Gas   Minerals commonly exhibit three types of inclusions: solid, liquid, and gas.   **Solid Inclusions:** These can manifest as needles, fibers, or crystals. Examples include rutile or tourmaline needles in rutile quartz, calcite crystals in emerald, olivine in diamond, and apatite in sapphire.   **Liquid Inclusions:** Shiny fingerprints are a form of liquid inclusion. Heat treatment can reduce these inclusions, but they are not as common. Liquids typically transform into gas or vapor during the mineral's cooling process.   **Gas Inclusions:** Present in the form of bubbles, gas inclusions occur during the solidification of melted substances. The shape of bubbles can help differentiate between natural and synthetic stones.   ### Classification of Gem and Mineral Inclusions: Phases Unveiled   Inclusions can exist in various phases, indicating the coexistence of different materials within a stone.   1. **Single Phase Inclusion:** Primarily solid, with gases occasionally found in glasses or synthetic stones. 2. **Two-Phase Inclusion:** Exhibiting two types of inclusions, such as solid and liquid. 3. **Three-Phase Inclusion:** Presenting three types of inclusions, often visible through UV light. 4. **Multiphase Inclusion:** A rare phenomenon with combinations of more than three phases, showcasing a variety of inclusions.   ### Inclusions in Natural vs. Synthetic Gemstones   Distinguishing natural gemstones from synthetic ones relies on the presence of specific inclusions.   **Inclusions in Natural Gemstones:** - Needles - Crystals - Fluids - Clous - Imperfect bubbles - Rutile hairs - Tourmaline hairs - Silk fingerprints - Twinning   **Inclusions in Synthetic Gems:** - Bubbles - Fingerprints   ### Tips for Viewing Inclusions   - Utilize optimal lighting conditions. - Employ a polariscope for testing. - Use UV light or fluorescent light for enhanced visibility. - Leverage a loop or mini microscope. - View the gemstone from various angles for a comprehensive examination.   In conclusion, understanding the world of gemstone and mineral inclusions is a fascinating journey that requires a keen eye and knowledge of diverse inclusion types. Inclusions, often seen as imperfections, serve as the keys to unlocking the authenticity and beauty of these precious stones. As research continues, the list of inclusion types evolves, providing gemologists and enthusiasts with new insights into the geological history of these captivating treasures.  

it's important to note that some imitations, such as high-quality resin, can mimic the physical properties and appearance of amber. Therefore, it's recommended to use a combination of these methods to determine the authenticity of a piece. Additionally, it's a good idea to have a sample tested by a reputable gemology laboratory for a more accurate determination.

Faceted Stones in Colored Stones are evaluated by Color, Cut, Clarity, Sizes. Among them, color is the king of all. The more intense will be the color with lighter tone, the more it will be valuable. Market trends play a vital role in defining value of a colored stone.

How can you assess the quality of a diamond when making a purchase, whether online or in person? Gemologists have established specific standards that, when adhered to during diamond analysis, prove invaluable in initially evaluating a valuable, high-quality diamond. What are these standards? How are they determined? Explore further details

How tektites are formed by extra territorial bodies such as meteorite collision impacts. This is only possible by hypervelocity meteorite collisions with terrestrial rocks. High energy, temperature and pressure is needed. 

Star phenoman in rubies and sapphires is common. That is due to their asterism or internal reflection. In cabochon form, star makes the low grade Corundum also valuable. Chemically, star sapphire is an aluminum oxide and forms as trigonal crystals.

There are different types of Crystal Structure by which you can recognize. Information about crystallization of any Gemstone and Minerals help us in identification. Researchers have divided crystals by Shape and by properties.