Abrasion: How to Care for Moldavite

01What is Abrasion Damage

Abrasion is a form of damage where the surface of moldavite is scratched or worn down. It can be natural, accumulated in the environment over time, or artificial, caused by improper packaging and transport.

02The Hardness of Moldavite

The Mohs scale measures a material's resistance to scratching, from 1 (very low) to 10 (very high). Moldavite has a hardness between 6.5 and 6.9 for most specimens (not 5.5–7 as some sources report: that range is too wide). This data comes from the researcher who authored the book Moldavites – The Czech Tektites (1994).

Any material of equal or greater hardness can scratch moldavite. This is why keeping it in a bag with other moldavites or quartz crystals ends up scratching it. It's also why it's often found nicked during extraction: in the surrounding sediments there are feldspar (Mohs 6) and quartz (Mohs 7), which scratch it when sifted.

03Natural Abrasion

Natural abrasion occurs during the transport of moldavite over millions of years, due to gravity (the stone rolling down a slope) or water (pushing it against other stones). The surrounding sediments — gravel, sand, and rocks like quartz, quartzite, feldspar, granite, and gneiss — often have greater hardness and, by rubbing, damage the moldavite.

04Artificial Abrasion

Improper handling, storage, packaging, and transport can ruin a moldavite. If it's not packaged well, with every movement the pieces rub against each other, and over time the surface wears down. Unfortunately, this happens due to lack of information, to save on shipping costs, or due to little respect for the stone. Moldavite should always be individually wrapped in plastic or tissue paper during transport.

05What Abrasion Looks Like

The surface of moldavite is normally sculpted with fine lines, grooves, channels, dimples, and sometimes sharp edges. Abrasion makes it more blunt, worn, rounded, and dull: the surface is literally scraped away and the stone loses size as it degrades.

The Stages of Abrasion

• Initial stages: part of the natural luster has been rubbed away, with dull areas and still shiny areas; the stone begins to lose its edges and become rounded.
• Intermediate-advanced stages: general rounding of the shape, scratched and worn surface, no residual edges, profile becoming oval; the dull surface makes the stone no longer transparent. If the cause persists, the moldavite will eventually be completely destroyed.

06Simulated Abrasion in the Lab

Abrasion damage has been reproduced in the laboratory to show its progression: a moldavite was rotated in a cylinder along with sediments similar to those surrounding it in the soil (gravel, sand, and rocks with quartz, quartzite, feldspar, granite, and gneiss). It shows how the luster changes, the edges are destroyed, and the shape wears down until it becomes oval.

07How to Prevent Abrasion

Prevention is easy, with a little care:

• When transporting it, wrap each moldavite individually in tissue paper or a resealable bag to prevent rubbing.
• If you carry it with you, keep it in a dedicated case, away from harder crystals or rocks.
• When storing it, leave a small space between the moldavite and any other stone, crystal, or rock, to avoid accidental contact.

An intact surface also contributes to the value of a specimen: discover how much it affects it in the 15-factor evaluation guide.

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