Introduction to gemstones and semi-precious stones starts with one simple idea: the label matters less than how a stone looks in real light, how it behaves once set, and how clearly it’s been described. This guide covers definitions, treatments, durability, and a stone-by-stone snapshot so you can choose gemstone jewellery with clarity and confidence.
What Is a Gemstone?
A gemstone is a mineral (and sometimes an organic material) cut and polished for jewellery. A gemstone earns its place through beauty, durability, rarity, and demand.
“Gemstone” describes the category, not the price point. Colour quality, cut, clarity, size, and treatment history determine how valuable, and how visually compelling a stone feels once it’s worn.
What Does “Semi-Precious” Mean?
“Semi-precious” is a historic label that separated diamond, ruby, sapphire and emerald from other stones. It is not a scientific classification, and it doesn’t map neatly to value.
Many semi-precious stones can feel distinctly high-end when colour and cut are exceptional, tourmaline and tanzanite are perfect examples. What matters is presence, durability, and transparent treatment disclosure.
Is Diamond a Gemstone?
Yes, diamond is a gemstone. Its reputation comes from durability and cultural value, but its pricing still depends on cut, colour, clarity, and whether it is natural or laboratory-grown.
Read more: Is a Diamond a Gemstone? Understanding How Gemstones Are Classified.
The 4 Things That Determine Gemstone Quality
The stone name is the starting point. These four factors decide whether a gemstone feels genuinely fine once it’s set and worn.
- Colour: tone, saturation, and how it reads in natural light
- Cut: symmetry and whether the cut supports colour (not just sparkle)
- Clarity: stone-specific expectations (some stones are meant to show character)
- Treatment: what’s been done and whether it’s disclosed
Image source: Argent & Asher
Gemstone Treatments: What They Are (and Why They Matter)
Treatments are common in gemstone jewellery, the key is transparency. Two stones can look similar online, but behave very differently long-term depending on what’s been done to them.
A gemstone treatment simply means a process has been used to enhance colour or clarity, or to stabilise the material. Some treatments are widely accepted, while others dramatically affect durability and value. The most important thing is that any reputable jeweller should disclose treatments clearly before you buy.
The Treatments You’ll See Most Often
- Heat treatment (common in sapphire and ruby): can improve colour/clarity and is generally accepted when disclosed.
- Oiling / resin filling (common with emerald): improves appearance, but can affect care requirements and long-term stability.
- Irradiation (seen with some topaz): creates bright colour; disclosure matters so expectations match the stone.
- Stabilisation (seen with turquoise): strengthens porous material; quality varies massively, so transparency is key.
If you’re browsing pieces and want to see how different stones are used in real designs, you can explore: Coloured Gemstone Jewellery. If you’re comparing stone types and labels, this guide also helps: What Are Semi-Precious Stones?.
Image source: Argent & Asher
Gemstone Durability: What’s Safe for Everyday Jewellery?
“Durable” doesn’t mean boring — it means the stone suits the job. A ring worn daily needs different behaviour than a necklace, and the setting can make a huge difference.
Durability is a blend of hardness (scratch resistance), toughness (chip resistance), and stability (how the stone responds to heat, chemicals, and everyday life). This is why two equally beautiful stones can be better suited to different pieces and why design matters as much as the gemstone choice.
A Practical Rule
If the piece is a ring (especially worn daily), prioritise stones with strong durability and pair them with a protective setting. If it’s a necklace or pendant, you have more freedom to choose stones for colour and presence without needing the same level of structural protection.
If you want to see how stone choice and setting style come together in finished pieces, explore: Coloured Gemstone Jewellery. If you’re deciding between stones, this comparison page is also useful: Compare Gemstones.
Gemstone Snapshot: The Stones People Ask About Most
This section is a beginner-friendly snapshot, what each gemstone is known for, what quality looks like, what to watch for, and how it tends to feel when set in fine jewellery.
Sapphire Gemstone
Sapphire is corundum (Mohs 9), which is why it’s a favourite for heirloom rings. The real quality marker is colour: a stone that holds saturation without going inky indoors.
- Quality cues: even colour, balanced tone, crisp cut
- Treatment: heat treatment is common; disclosure matters
- Design note: the best sapphires look rich rather than theatrical
Emerald Gemstone
Emerald is beryl (Mohs ~7.5–8) and inclusions are expected, they’re part of its identity. Very clean emeralds tend to sit at the top end of fine jewellery, so transparency around clarity enhancement matters.
- Quality cues: depth of green, even distribution, a “lit-from-within” look
- Treatment: clarity enhancement is common; the degree matters
- Design note: emerald is about mood and richness, not perfection
Image source: Argent & Asher
Ruby Gemstone
Ruby is red corundum (Mohs 9). The most desirable rubies glow with saturation, but “true red” is rarer than people assume, many commercial stones skew darker or browner.
- Quality cues: saturation, lively light performance, balanced tone
- Treatment: heat treatment can be common; disclosure matters
- Design note: strong pink tourmaline can feel just as impactful on colour alone
Tourmaline Gemstone
Tourmaline (Mohs ~7–7.5) is one of the most colour-diverse gemstones, green, pink, red, teal, bi-colour and everything in between. It’s a colour lover’s stone, and when chosen well it reads modern and intentional.
- Quality cues: clean tone (less grey), strong saturation, good cut
- Watch for: dullness in low light if tone is too dark
- Design note: teal tourmaline has a quiet depth that feels distinctly current
Tanzanite Gemstone
Tanzanite is a variety of zoisite (often Mohs ~6–7) known for blue-violet depth and pleochroism (colour shift with angle/light). It can feel luxuriously velvety when the tone is right.
- Quality cues: saturated blue-violet, clarity that supports glow
- Treatment: colour enhancement can be common; disclosure matters
- Design note: strong in pendants; rings benefit from protective settings
Aquamarine Gemstone
Aquamarine is beryl (Mohs ~7.5–8) and valued for clarity and a cool, restrained blue. It’s quietly elevated when the tone is clean and the cut is crisp.
- Quality cues: transparency, even tone, brightness without looking icy
- Watch for: grey undertones that flatten the stone
- Design note: reads refined in minimal gold settings
Image source: Argent & Asher
Turquoise Gemstone
Turquoise (often Mohs ~5–6) is an opaque stone prized for colour authority. It doesn’t compete with diamonds, it anchors a piece through saturation and symbolism.
- Quality cues: strong saturation, stable surface, intentional matrix
- Treatment: stabilisation can be common; it should be explained
- Design note: framed in gold, turquoise looks architectural and bold
Lapis Lazuli
Lapis (often Mohs ~5–5.5) is valued for deep ultramarine colour. The best lapis feels velvety, with subtle pyrite that adds contrast rather than chaos.
- Quality cues: deep blue tone, minimal white calcite, good polish
- Watch for: pale, chalky stones that lose impact once set
- Design note: lapis is graphic, confident, and dramatic in gold
Topaz Gemstone
Topaz (Mohs 8) can be beautifully bright and clean. Many blue topaz stones are treated from colourless material; that’s normal - what matters is clarity in description and a tone that feels intentional.
- Quality cues: crisp cut, clean tone, brightness without harshness
- Treatment: common for blue; should be disclosed
- Design note: shines when used for light and clarity, not trend colour
Image source: Argent & Asher
Amethyst Gemstone
Amethyst (Mohs 7) is quartz and its value comes from colour. The best stones have strong violet tone without muddy brown undertones.
- Quality cues: even saturation, clear violet, good transparency
- Watch for: dullness or brown tone that makes it feel flat
- Design note: amethyst next to turquoise feels deliberate and modern
Image source: Argent & Asher
Zircon Gemstone
Zircon is a natural gemstone often confused with cubic zirconia (which is synthetic). Zircon can show serious brilliance and fire when well cut, with colours including blue and champagne.
- Quality cues: lively light return, clean facet pattern, good polish
- Watch for: confusion with CZ - naming should be explicit
- Design note: best when chosen for optical performance, not comparison
What We Look For at Argent + Asher
At Argent + Asher, gemstones are chosen for how they perform once set in gold, not just how they look in a studio photo. We prioritise colour presence, clean tone, and settings that protect the stone while keeping the design feeling refined.
- Colour before size
- Even saturation and clean tone
- Clear treatment disclosure
- Considered settings designed for long-term wear
- Real-light beauty, not marketing shine
Where to Go Next
If you want to continue from this introduction, these guides build naturally:
- What Are Semi-Precious Stones? Meaning, Examples, and Value Explained
- What Are the Most Popular Gemstones? Colours, Value and Why They’re Chosen
- What Is a Blue Gemstone Called? A Guide to Sapphire, Turquoise, Topaz and More
- Gemstone Jewellery: How to Choose the Right Stone, Setting, and Quality
- Semi-Precious Stone Jewellery: What Impacts Price and Quality?
- Semi-Precious Gemstone Necklaces: What to Look For Before You Buy
Frequently Asked Questions About Gemstones and Semi-Precious Stones
Best places to buy gemstones and semi-precious stones online UK
The best place depends on transparency. Look for treatment disclosure, specific stone descriptions, solid 14k or 18k gold settings, and realistic pricing. At Argent + Asher, we focus on solid-gold gemstone jewellery and explain how tone, treatment and setting design affect how a gemstone performs once it’s worn.
How to identify genuine semi-precious stones from synthetic ones
Start with disclosure. A reputable seller should state whether a stone is natural, treated or laboratory-created. Pricing that feels unrealistic is often a warning sign. At Argent + Asher, we’re transparent about materials and will explain what a gemstone is, how it is set, and what that means for long-term wear.
Best places to get custom gemstone jewellery made in London
Choose designers who understand gemstone behaviour and structural setting. A proper process includes transparent sourcing, treatment clarity, previews (sketch or CAD), solid gold options, and guidance on what stones suit the style you want. Argent + Asher is London-based and we design gemstone jewellery with structure in mind so the stone choice matches how the piece will be worn.
Top UK jewellery brands specialising in gemstones and semi-precious stones
Strong brands prioritise colour integrity, setting quality and transparency. Look for solid gold settings, clear treatment disclosure, and consistent design standards. Argent + Asher approaches gemstones through a design lens, selecting stones for saturation and presence once set in gold.
Affordable semi-precious stone rings available in UK stores
Affordable can still mean high quality when colour and setting come first. Prioritise saturation over size, avoid plated metals, check the security of the setting, and confirm treatments. At Argent + Asher, we often recommend choosing colour integrity and secure design over carat weight, particularly for stones such as tourmaline and amethyst.
Where to get custom gemstone jewellery made in the UK
Look for jewellers who disclose treatments, explain durability clearly, and design with protection in mind. Solid 14k or 18k gold options and a clear approval process are essential for custom work. Argent + Asher creates custom and made-to-order gemstone jewellery with an emphasis on long-term wear, considered setting design and material transparency.
What should I check before buying gemstone jewellery online?
Check transparency on stone type, treatments and metal quality; look for photos in natural light, a detailed description of colour and cut, and solid 14k or 18k gold where possible. At Argent + Asher, we select gemstones for presence once set in gold, tone, saturation and structure matter as much as the stone name.
Do gemstones get treated, and does that matter?
Many gemstones are treated, such as heat treatment in sapphire or clarity enhancement in emerald. Treatment is not automatically a negative, but disclosure matters because it affects value, stability and care.
