Mineral Identification Chart: Properties of Common Minerals

A mineral identification chart is a lookup table: you measure a few properties of an unknown specimen, then find the row that matches. No single property names a mineral, but combined — hardness, streak, luster, color, and cleavage — they converge on one answer. Below is a reference chart for ten of the most common minerals you are likely to find, followed by how to use it with simple at-home tests.

Common mineral properties chart

Hardness is on the Mohs scale (1 = softest, 10 = hardest). "Streak" is the color of the mineral's powder on unglazed porcelain. Where a mineral has a signature test, it is noted in the last column.

How to use the chart

Treat each property as a filter that removes candidates. Work through them in this order for the fastest result:

1. Luster first. Is it metallic (pyrite, magnetite) or non-metallic (everything else)? This splits the chart immediately.
2. Hardness next. Try your fingernail (~2.5), a copper coin (~3), a steel nail (~5.5), and a glass plate. If your fingernail scratches it, you are looking at talc, gypsum, or mica. If it scratches glass but a nail can't scratch it, think feldspar or quartz.
3. Streak. Especially useful for the metallic minerals — pyrite's greenish-black streak versus magnetite's black streak.
4. Cleavage. Does it peel into sheets (mica), break into cubes (halite, galena), leaning rhombs (calcite), or fracture with no flat planes (quartz)?
5. Confirm with color and a key test. Only now use color, and run the signature test — acid on calcite, a magnet on magnetite, a taste of salt on halite.

Worked example: telling three white minerals apart

Quartz, calcite, and gypsum can all appear white or colorless, so color is useless here. The chart's other columns separate them instantly:

• Gypsum is so soft your fingernail scratches it (hardness 2).
• Calcite resists a fingernail but a nail scratches it (hardness 3), and it fizzes in acid.
• Quartz scratches both the nail and glass (hardness 7) and does not react to acid.

Three quick tests — fingernail, nail, and a drop of vinegar — and three look-alike white minerals are fully resolved. That is the whole point of a chart: it turns a vague color impression into a decision tree.

For the full method behind each property, see our guide on how to identify minerals. And to catalog your finds, compare specimens, and ask an AI geologist follow-up questions, the Stone Sense mineral identifier app keeps your growing collection organized.

Frequently asked questions

How do I use a mineral identification chart?

Test the properties you can measure at home — hardness, streak, and luster — then find the row that matches all of them. Use color last, only to confirm a match you have already narrowed down, because color alone is unreliable.

What are the most common minerals?

Quartz, feldspar, and mica make up much of granite and many rocks; calcite dominates limestone and marble. Halite, pyrite, gypsum, talc, fluorite, and magnetite round out the ten most frequently encountered minerals.

Which minerals have a metallic luster?

Among common minerals, pyrite (brassy, greenish-black streak) and magnetite (black, magnetic) are metallic. Most others — quartz, feldspar, calcite, gypsum — are non-metallic, usually glassy or pearly.

How can I tell calcite from quartz?

Hardness and acid settle it: calcite is soft (3) and fizzes in vinegar; quartz is hard (7), scratches glass, and does not react. Calcite also cleaves into leaning rhombs, while quartz fractures with curved surfaces.