Mottramite

Mottramite is a lead copper vanadate mineral in the descloizite group. Most pieces you’ll see for sale run dark green to almost black, and they usually show up as botryoidal crusts, drusy coatings, or those chunky, glittery masses, not neat little standalone crystals.

Grab a decent specimen and the first thing that hits you is the heft. It just drops into your palm like it means business, especially if you’re used to lightweight quartz or calcite, and that’s the lead making itself known. From across the room the surface can look almost velvety. Up close, though, it’s more like a tight carpet of micro-crystals (the kind that can snag on a fingertip if you slide it the wrong way) and it’ll toss back tiny green flashes when you tilt it under a lamp.

Mottramite is often mistaken at first for other green, crusty minerals, especially malachite or conichalcite. Its color tends to be deeper, from olive to bottle-green. The luster is waxy to resinous, unlike the brighter, silkier look malachite can show. A porous limonite or gossan matrix also points to an oxidized lead deposit, a setting experienced collectors recognize quickly.

In 1876, the German mineralogist Gustav Adolf Kenngott was the one who first described mottramite. He called it “mottramite” after Mottram St. Andrew, a village in Greater Manchester, England, because that’s where the mineral showed up in local lead workings.

Some collectors assume mottramite is an English mineral found only in the UK. That is no longer the case. English material still matters for the name and history, but the most striking specimens, with a heavy, slightly waxy luster that shows when tilted under a lamp, mostly come from classic oxidized zones in places such as Namibia and Morocco.

Mottramite forms in the oxidized zones of lead and copper deposits and is best known from places like Tsumeb (Namibia) and Touissit (Morocco), plus classic localities in Arizona.

Look at where mottramite turns up and you’re basically reading the “weathered” chapter of a deposit. Down deeper it’s primary sulfides. Then oxygen and groundwater start doing their slow, stubborn thing near the surface, and all of a sudden vanadium, copper, and lead can finally run into each other and freeze into those dense vanadate minerals.

Most specimens occur as thin coatings or botryoidal crusts on limonite, quartz or other oxidized gossan material, which can leave rusty residue on the fingers. It is also found intergrown with close relatives in the descloizite group, and sometimes beside green copper arsenates and phosphates. Field identification is difficult because the oxidized zone is a mixture of minerals, and specimens only two inches apart can look like different species. Confident identification often requires lab testing.

Color: Usually dark green, olive green, brownish green, to nearly black; thin edges can show a clearer green in strong light. Some pieces have yellow-green highlights where the crystals are finer.

Luster: Resinous to waxy, sometimes slightly vitreous on fresh micro-crystal faces.

Pick up the specimen and judge the heft. Mottramite feels unusually dense for a green crust, and that weight cue is one of the best tells in hand. If you scratch it with a steel nail, it should scratch, but not like soft malachite that gouges easily; you’re in that mid hardness range. And a 10x loupe helps a lot, since mottramite often shows a fine sparkly druse that malachite’s fibrous texture doesn’t mimic.

Mottramite is sometimes confused with these materials:

• Dioptase (dark green druse can read like mottramite in photos, but dioptase is glassier and usually shows sharper micro-crystals)
• Malachite (botryoidal green crusts; sellers sometimes slap “mottramite malachite” on mixed pieces)
• Conichalcite (green botryoidal/drusy crusts from the same kinds of oxidized copper zones, often sold interchangeably in lots)
• Duftite (another green lead-copper arsenate; it can look like a dead-ringer when it’s a fine drusy coating)
• Dyed howlite or dyed magnesite sold as “green mineral druse” (color pools in pits and cracks and the base stays chalky white under chips)
• Green glass “mineral” lumps (too uniform, too glossy, and it feels weirdly light compared to real lead-bearing mottramite)

Mottramite can be handled like an ordinary cabinet specimen, but as with any lead-bearing mineral it should be kept away from food and drink. The main risk is not touching it but the dust produced if it is damaged, chipped or worked.

Wash hands after handling. Keep specimens out of reach of children and pets. Avoid raising dust, since fine powder can stay airborne longer than expected. If cutting or scrubbing is unavoidable, work wet and wear suitable respiratory protection to avoid breathing in the particles.

Rough/Tumbled: $25 - $400 per specimen

Prices swing all over the place depending on where it came from and how much it catches the light. A dull, dark crust? That’s usually cheap. But a bright green, drusy botryoidal piece sitting on a clean matrix from a known mine can jump in price fast, especially when you tilt it and the tiny crystals flash back at you.

Nondurable — Scratch resistance: Fair, Toughness: Poor

It’s stable on the shelf, but the crusty habit can chip and edge-wear easily if it rattles around in a box.

Use & Storage

Store it in a padded box or cabinet tray where it cannot rub against harder pieces. Wrapping each specimen helps, because botryoidal surfaces can bruise on the high spots.

Cleaning

1) Use a soft, dry brush to remove loose dust. 2) If it needs more, use a slightly damp cotton swab and dab, don’t scrub. 3) Dry fully right away and avoid soaking.

Cleanse & Charge

Stick to smoke, sound, or a quick sit on a dry selenite plate, and keep it out of water. If you leave it in the sun, check it now and then since dark greens can look flatter over time.

Placement

A stable shelf position is best, ideally with light that grazes the surface so the druse flashes. Placing it near a lamp works better than in a window.

Caution

This piece has lead and copper in it. So don’t use it in water, don’t make gem elixirs with it, and try not to create any dust (like from scraping, sanding, or grinding). Wash your hands after you handle it, and keep it away from kids and pets.

Mottramite is valued mainly as a collector's mineral, prized for velvety drusy crusts that flash small green reflections under a lamp. Its name comes from Mottram St. Andrew in Greater Manchester, England, where it was found in lead workings and later described by Gustav Adolf Kenngott in 1876. Display specimens are usually kept in cabinets or trays instead of being worn or handled often.

In crystal traditions, mottramite is associated with the Root and Heart chakras, the zodiac signs Capricorn and Virgo, and the element Earth. Practitioners tend to link its weight and dark color with grounding and steady focus, and some keep a piece on a desk during routine work. These are cultural beliefs, not proven effects, and they do not replace medical care. Because it contains lead and copper, it should not be carried loose, placed in water or used in elixirs, and hands should be washed after handling.