Topaz Stone Guide
By Jared James · Last updated 17 May 2026
Quick answer
Topaz is a durable gemstone at 8 on the Mohs scale, available in colours from the prized golden imperial topaz to popular blue topaz. Most blue topaz is colourless topaz treated by irradiation and heat to produce sky, Swiss or London blue.
What topaz is
Topaz is aluminium silicate with fluorine and hydroxyl in the crystal. It forms in large clean crystals and is one of the harder gemstones. The catch is that topaz has perfect cleavage in one direction, meaning it can split cleanly if struck at the right angle on a corner.
Colour and look
Imperial topaz is golden orange to pinkish orange and is the rarest variety. Blue topaz comes in sky blue (light), Swiss blue (vivid medium) and London blue (deep, slightly greyish). Pink topaz is rare in nature. Colourless topaz is sometimes cut as a diamond simulant. Mystic topaz is colourless topaz with a thin metallic coating that creates a rainbow effect.
Hardness and durability
Topaz is 8 on the Mohs scale with good scratch resistance. Cleavage is the main weakness, so a sharp knock on a corner can chip or split the stone. Setting style matters. A bezel or low-profile prong with rounded corners gives topaz a long life as a ring stone.
What to look for
For imperial topaz, colour saturation and purity drive value. For blue topaz, colour preference matters more than rarity since the colour is treated and consistent. Clarity should be eye-clean across the range. Cut quality matters because well-cut topaz returns excellent light.
Treatments and origins
Most blue topaz starts as colourless material and is irradiated then heat treated to a stable blue. The treatment is permanent. Imperial topaz is usually untreated. Mystic topaz has a coating that can scratch off over time. Imperial topaz comes primarily from Ouro Preto in Brazil. Blue topaz starts in Brazil, Sri Lanka and Nigeria.
Best uses
Blue topaz earrings, pendants and dress rings are popular because the colour is striking, the stone is durable and big stones are cheap. Imperial topaz makes a luxurious cocktail ring or pendant, especially in yellow gold. Topaz works for engagement rings in protective settings with rounded edges.
Care
Clean with warm soapy water and a soft brush. Ultrasonic is generally safe but avoid for stones with visible fractures or coatings. Protect from sharp impacts on edges and corners because of the cleavage. Store separately from harder gems.
Price
Blue topaz is one of the cheapest fine gemstones in larger sizes. Large eye-clean Swiss or London blue topaz over 5 carats is realistic on a modest budget. Imperial topaz is far more expensive per carat because it is rare and almost always untreated.
Designing a custom ring
Start a custom design
Coloured-stone engagement and dress rings are made to order. Tell us what you have in mind and we will help you compare stone options, metal choices and settings.
Start a custom designFrequently asked questions
- Is blue topaz natural?
- The blue colour in most blue topaz is created by irradiating and heating colourless natural topaz. The stone itself is natural. The colour is stable and permanent.
- Is topaz strong enough for an engagement ring?
- At 8 Mohs hardness, topaz resists scratching well. The main concern is cleavage, which can cause chips on sharp corners. A protective setting and gentle wear extend the life of a topaz ring.
- What is imperial topaz?
- A naturally golden orange to pinkish orange topaz, mostly from Ouro Preto in Brazil. Imperial topaz is far rarer than blue topaz and almost always untreated.
- Is mystic topaz the same as topaz?
- Yes, with a thin metallic coating applied to the back to create a rainbow effect. The coating can wear or scratch off over time, so mystic topaz needs gentler handling than other topaz.
Still deciding
Talk through topaz with us
Send what you have in mind, even if that is only a colour, a budget and a piece of jewellery type, and we will help you compare options.
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