条痕（英语：streak）是指矿物划过粗糙表面而留下的，或磨成的细小粉末之颜色。

一种矿石表面的颜色常有很大的变化空间，而其不同样品的条痕色却变化很少，因此条痕对矿物的辨别和分类十分重要，特别是不透明或有色矿物。如果当矿石划过条痕板时无明显条痕可见，那幺其条痕将会被称为白色或无色。对于硅酸盐矿物来说条痕却并不很重要，因为这类矿物中多数条痕为白色，并且硬度高而难以被打成粉末。

矿物外观颜色因含有杂质或被扰乱的宏观晶体结构而变化。某些杂质吸收某特定波长光波的能力极强，就算含量很少也可能从根本上改变该矿石总体反射的光波长度，因此有颜色上的变化。但当矿物标本在条痕板上拉过而产生条痕时，样本被细分成极小的晶体，此时少量杂质对光的吸收影响不大。

The streak (also called "powder color") of a mineral is the color of the powder produced when it is dragged across an un-weathered surface. Unlike the apparent color of a mineral, which for most minerals can vary considerably, the trail of finely ground powder generally has a more consistent characteristic color, and is thus an important diagnostic tool in mineral identification. If no streak seems to be made, the mineral's streak is said to be white or colorless. Streak is particularly important as a diagnostic for opaque and colored materials. It is less useful for silicate minerals, most of which have a white streak or are too hard to powder easily.