Tumbled Stones: What Grade to Buy

Cartoon of a man with an empty wallet deciding between a box of £2 tumbled stones and a single stone in a glass case priced £20

How Tumbled Stones Are Graded

Collecting tumbled stones is a great way to build a large and varied collection of crystals without taking up too much space.

Although sometimes called tumbled gemstones, this term is misleading. The grade of material used for tumbling is very rarely gem-grade. Any rock or mineral of that quality would be used for gemstones.

The grading system for tumbled stones varies depending on where the original material has been mined and its quality. Once tumbled, triple A grade (AAA) is used to describe the finest-grade stones. It's a higher grade than AA, which is higher than A.

Many businesses prefer to grade tumbled stones simply as A, B, C, or D. I sometimes use the term 'AAA grade' if a stone is exceptional, but otherwise, I find A, B, C, or D is adequate.

It's important to understand that a grade A, or a AAA grade tumbled stone means the finest grade of material that's tumbled. It doesn't mean the finest grade of the mineral.

Top-grade lapis lazuli, sugilite, charoite, and ruby zoisite, to name just a few, would never be tumbled; that quality of material goes to gem cutters, carvers, or is sold to collectors.

Emerald is a good example. We sell grade A tumbled emerald, but strictly speaking it's green beryl. For green beryl to be classed as emerald, it must exhibit certain characteristics. Stones that do not reach this grade should be classed as green beryl. However, for marketing and simplicity, it's often described as emerald.

The necklace in this photo, which is from our collection, features high-quality emeralds. They're not the finest by any means, but they are a high grade. This quality would never be tumbled, for obvious reasons.
Fine emerald gemstone necklace

Charoite and sugilite are both rare minerals. Charoite is extremely difficult to source because of the trade restrictions currently in place with Russia. Charoite cannot be found anywhere else in the world.

With a stone such as sugilite, not only is it difficult to source, but it's extremely expensive. We currently have grade C sugilite in our collection. We're selling them with minimal profit because, with our normal markup, they would be out of most people's budgets. £17 for a tumbled stone is expensive.

I have seen higher grades being sold for less than this price, but I'm not convinced they're genuine sugilite.

Rocks, minerals, and gemstones are graded according to colour, clarity, the presence or lack of impurities and inclusions, and market value.

A tumbled stone with a lower grade is not necessarily any less beautiful than a AAA-grade stone. It may just have a different appearance. Sometimes, the characteristic that causes a tumbled stone to be a lower grade can make it even more striking.

Beauty is subjective, so what one person finds beautiful, another may not.

Our grade A prehnite tumbled stones are virtually inclusion-free, while our grade B prehnite is heavily included. Although the grade A stones have amazing colour, the inclusions in the grade B stones make them far more striking, and no two crystals are the same.

A tumbled stone could be classed as grade D because it's heavily included, because of its colour, or because of another natural imperfection.

In some cases, it may contain more of the rock matrix than pure mineral. The rock matrix is the surrounding material or host rock in which the mineral formed.

Some stones, such as rutilated and tourmalinated quartz and star rubies and sapphires, are graded according to the quality of their inclusions. A stone with fewer inclusions is likely to be a lower grade.

Other optical phenomena are also taken into consideration. Labradorite with a distinctive blue flash will be more expensive than a stone with minimal iridescence.

two photos of prehnite tumbled stones, the stones in one photo are inclusion free, in the second photo they're included

Inclusions and anomalies in rock and minerals offer a glimpse into their journey through time. A distinctive mark or variation in colour is a good indication of the presence of another mineral or substance.

Internal fractures and surface-reaching fissures often occur during the crystal's early formation.

Many crystal websites proudly claim they only sell the finest-grade tumbled stones. The problem with that is that some material may be outside of some people's budget. It's evident from the amount of tumbled stones being sold on eBay and Amazon that some people are happy to buy cheaper stones.

The other issue is that by not selling the lower grades, a collection will not include all varieties of the stone, as the prehnite above shows.

There's a common misconception, especially amongst those who use crystals for healing, that the finest-grade tumbled stones have stronger energy. In crystal healing, a low-grade piece of rose quartz is no different from one that's far more expensive. The only difference is aesthetics.

The late Judy Hall, author of the Crystal Bible books, says a broken or damaged crystal will often be even more powerful.

Never be put off by the grade of a tumbled stone. All rocks and minerals are unique and have their own charm and geological significance.

In our collection, we feature stones of all grades and even have an Empathic Warrior collection. These are stones that have become damaged at some point during their journey, so we sell them at a significantly reduced price.

When shopping for crystals, buy a stone because you like it, are drawn to it or because it's suitable for your needs. Don't choose a higher grade or more expensive piece simply because you believe its energy will be stronger.

Part of the beauty of rocks and minerals, and nature in general, is that nothing is the same, and nothing is perfect. Embrace the diversity and appreciate the nuances.