What Is Black Sand?

If you pan for gold, black sand shows up in your very first pans. It is heavy, it is dark, and it sits right where the gold sits. This page explains what it is, why it follows gold, and what to do about it. The guides listed below go deeper.

What is black sand made of?

Black sand is a mix of heavy minerals, not one single thing. Magnetite, a black iron mineral, is usually the biggest part. The U.S. Geological Survey's guide to prospecting for gold names magnetite as the most common mineral in black sand. It lists others that can turn up too, like ilmenite, chromite, monazite, cassiterite, small amounts of platinum group metals and even some gemstones.

A panning guide from the U.S. Forest Service and the Bureau of Land Management adds garnet, zircon and scheelite to the list. Garnet is easy to pick out by eye, as small red grains.

The mix changes from creek to creek. In one part of Idaho, USGS geologists found ilmenite was more common than magnetite, because groundwater there had slowly dissolved much of the magnetite away.

Why is black sand found with gold?

Because both are heavy, and moving water sorts things by weight. Ordinary sand is less than three times as heavy as water. Black sand minerals run about four to just over five times as heavy as water. Gold is heavier still.

Fast water carries the light sand along. When the current slows, in crevices, behind boulders and on the inside of bends, the heavy material drops out first. Gold and black sand end up resting in the same low spots. That is why prospectors look for gold where black sand has gathered.

A layer of black sand tells you the water dropped heavy material in that spot. It is a good sign for a place to dig, but it does not promise gold.

Is black sand magnetic?

Part of it is. Magnetite is strongly magnetic, so a magnet lifts it easily. Ilmenite and chromite answer a magnet only weakly. Garnet and zircon are not magnetic, and hematite barely reacts unless it has some magnetite mixed in.

A magnet is also an easy way to identify magnetite. A USGS report on Idaho black sands suggests just that: test it with a magnet. In a normal pan, our magnet pulls up all the black sand we see. Any heavy grains that are not magnetic stay behind, and a little more panning finishes the job. Our guide What Is Magnetite? shows how to tell magnetite from hematite with a magnet and a streak test.

How do you get black sand out of your pan?

You can do most of it right in the pan. Pan your material down until mostly black sand and gold are left, keep a little water in the pan, and pass a magnet over it to lift the magnetite out. A quick final pan takes care of the rest. Our step by step guide, How to Separate Gold from Black Sand, walks through each stage. A black sand magnet takes care of the magnetite part.

What is black sand used for?

On an industrial scale, quite a lot. Heavy mineral sands are mined for titanium, which comes from ilmenite and rutile, for zirconium from zircon, and for rare earth elements from monazite. Magnetite is the most commonly mined iron ore, and the USGS reports that almost all iron ore, 98%, goes into making steel.

Those are large mining operations, though. For most panners, the reason to care about black sand is the fine gold that may be hiding in it.

Is black sand dangerous?

For most panners, the main trouble with black sand is that it hides fine gold. One thing is worth knowing, though. Some black sand deposits contain mildly radioactive minerals. In the Idaho black sands it studied, the USGS found these were mostly monazite and euxenite. That is a feature of certain deposits, not of black sand in general. If you plan to work a deposit known for these minerals, your state geological survey is a good place to ask first.

Is beach black sand the same thing?

No. The black sand on some Hawaiian beaches forms when lava hits the ocean, cools fast and shatters into grains. The National Park Service describes this at Hawaii Volcanoes National Park. The black sand in a gold pan is different: it is heavy minerals sorted out of a creek's gravel by moving water.

Where should you start?

If black sand is getting in your way right now, start with the separation guide. If you want to know what you are actually lifting out of the pan, read the magnetite guide next. All of our black sand guides are listed below.