peach 2
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> peach
> 
> peach, sb.2 Min. local. f. prec.: see quot. 1811. Cornish miners'
> term for chlorite slate (see chlorite1 2); also distinguished as
> 
> green peach
> 
> green peach.
> 
> blue peach
> 
> blue peach: see quots. 1877, 1881.
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>    * 1778 Pryce Min. Cornub. 325 When a load is composed mostly of
>      this sort of stone, it is called a peach.
> 
>    * 1811 Pinkerton Petral. I. 128 Chlorite..is the green talc of
>      Born, and the Samnterde of old German writers, perhaps from its
>      velvety appearance. To the Cornish miners..it is also known by
>      the name of peach.
> 
>    * 1877 Min. Mag. I. 75 The green peach of the Cornish tin mines
>      is undoubtedly chlorite... Blue peach..is probably a
>      bluish-gray variety of Tourmaline.
> 
>    * 1881 Raymond Mining Gloss., *Blue peach, Corn., a slate-blue,
>      very fine-grained schorl-rock.