About Materials

In this page, we will cover about the materials that we use on our jewellery, some of the terminology used in the industry, and the definitions behind it. Please refer to this page before purchase to understand fully our range of products and what to expect from Autium. Or please contact us at marketing@autium.sg or by phone +65 8847 4808 for any questions and clarifications. 


Gemstones or often referred as gems, are mostly minerals that are formed and then cut, polished for mainly jewellery purposes. Some gems like pearl or amber are not minerals, they are organics material made by living organisms. Main stone stated in the product listing is the gems that act as the center attention of the design. While melee is a term for tiny stones weigh under 0.15 carat, mostly used as accent stones for jewellery designs. 

Natural, Synthetic, and Imitation

All of our gemstones sold separately or on the jewellery pieces are natural. Natural means that it is formed in nature that takes million of years to form. No two gemstones that are alike even if they come in a pair, each of them is unique. Natural gemstones are rarer and more valuable. The opposite of natural will be synthetic, which are gems that made in labs by duplicating their natural counterparts. Hence, synthetic gems usually share the same physical and optical properties of the natural gems. On the other hand, imitation gems are any materials that presented as other gems. For example, a citrine that is sold as a yellow sapphire is an imitation. 

Treated and Untreated

Gemstones treatments are common practices in the industry. Please note that treated gems are still natural gems and not synthetic. Unless our product is stated to be unheated, it means the gems are treated. Treated means the gems are enhanced to improve the colour and overall the quality of the gemstones. Most of the gemstones sold in the industry are treated especially semi-precious stones, and you can expect decent to very good quality from treated gems.  The most common gems treatment is by heating, hence many times the terms "Heated" or "Unheated" often used to describe whether the gems are treated or not. Learn more about other gems treatments.

Untreated means there is no alterations or enhancements to the gems, they remain in the same condition as when they were extracted from the earth. Since there's no enhancements, it is very common that untreated gems have darker colour and more visible inclusions. Untreated gems that have high quality as treated gems, will be considered extremely rare, collector's worthy pieces and high prices. 


Inclusions are natural minerals or materials that is trapped inside the minerals while it is forming into crystals. Inclusions can be in any form of lines, bubbles, or cloud. All types of gemstones that are natural will have inclusions in them, it is naturally normal and unavoidable, different than synthetic gems that are made perfect without any inclusions inside. Gems treatments also used to reduce the appearance of inclusions, hence untreated gems will have more inclusions compared to treated gems.

Depends on the way it is cut and the size of the stone, some inclusions required using 20x magnification by loupe to properly see them. Inclusions that is not visible by eyes only is called naked eye clean. The bigger the stone, the easier for the inclusions to show. This also means that the bigger size stone with less inclusions will be rare and high prices. Autium embraces all materials including of their inclusions, as they are natural occurrences that makes each of them unique.   


By request, we provide certifications provided by official certification institutes such as Nanyang Gems Institute, Universal Gems Institute and GIA / HRD / IGI or other establishments. Please contact us for more info.

Diamonds and Cubic Zirconia

Diamond is made of carbon and considered the hardest material or stone in the world with hardness 10 in the Mohs Scale. Diamond forms under high temperature and pressure conditions that exist only within a specific depth range beneath the earth’s surface. Autium offers GIA diamonds, colourless as well as other coloured diamonds. Please book an appointment with us for more about our diamonds.

Cubic Zirconia or also called CZ, is a synthetic alternative to diamonds, that is made of the cubic crystalline form of zirconium dioxide. CZ is created in the lab, with hardness 8.5 Mohs scale, slightly lower than diamonds. It is still considered very durable for jewellery uses and the number one cost friendly alternative to diamonds.


As a brand that started with metals innovations, Autium is fully knowledgeable in metals. Our metals that we offer range from platinum, titanium, 22k yellow gold, and most commonly used are 18k gold and 925 silver. 

All Autium products have gone through quality check before delivery or collected by customers. However, eventually due to the wear and tear rule, the metals might become loose or out of shape. For example, some stones might fall out along the time due to the looseness of prongs, or a ring that becomes deformed. If these things happen, please reach out to our refurbishment services and our team will help you as much as we can.

24K gold is the highest purity of gold with 99.99% gold content, hence 24K gold jewellery is also known with a 999 hallmark. 24K gold is very precious material with good properties for jewellery. However, they are also very soft. So 18K gold is created by mixing alloys to 24K gold, to make the materials more durable for jewellery wear. 

18K Gold

18K gold means 18/24 part of gold, or it consists of 75% of gold and the rest are other metals that we often mix are silver, palladium, or copper. We do not mix with nickel, zinc or other types of metals. If you have any concern regarding any allergic reaction, please double check with your physician for advise on metal allergies. Please check our terms of service.   

18K gold jewellery is marked with 750 hallmark. By mixing different colour alloys accordingly, then we can create different intensity of 18K white gold and rose gold. 18K gold is commonly used for jewellery as it is more durable, and it has the nicest colour - not too yellow or too pale. 

Even if 18K gold is a hard material, it also depends partly on the design and dimension of the product. A thin wire of 18K gold, is still easily bendable by hand compared to a thick rod of 24k gold. Hence the jewellery is still prone to scratches or dents if not taken properly. In the meantime, please refer to our jewellery care to understand how to care for your jewellery. 

925 Silver

925 silver also known as Sterling silver means it consists of 92.5% of silver and the rest is mix with copper. The hallmark for sterling silver will be 925. Pure silver is also considered soft materials, hence mixing with alloys increase the hardness and durability of this material. Our 925 silver can be plated with a layer of 18K gold as additional protective layer, and it will appear exactly similar to 18K gold jewellery. Customers then may choose the colours to plate the silver - white, yellow, or rose gold. 


Hallmarking is governed by CASE, SAO, Singapore Jewellers Association standards of purity and is voluntary in Singapore. Based on ethical standards by the craftsmen and requirements claimed by us, we follow exact precious metals composition stated in our invoice. Hallmarking will be provided on our products based on designs. Please note a minimum space is needed for hallmarking, so designs with space limitations (for example, thin wire or simple basket) might not be able to be marked. Based on CASE, hallmark is on a voluntary scheme, hence we are also not obligated to hallmark our pieces. Please refer to CASE for more details or learn more about hallmarking here


Size Guides

When you purchase from us, we hope to customise the right size for you. The right size should not be too loose or too tight. Before purchase, please refer to our sizing guides here to determine your size for rings, bracelets, and necklaces.

Under the product in your cart, you will find a note box where you can also request for the size that you want. After transaction is made, our designer will reach out to you through email or phone number that you provided during checkout to confirm on the final size. 

Please contact us at marketing@autium.sg or +65 8847 4808 for any questions. Refer to our size exchange policy here