RED STAIN ON,IN, ROCKS

[605dano]

I find a lot of this red stained rock in veins and was was wondering if it is just iron or could be something else. Sometimes it's just a surface coating, but sometimes it penetrates the rock.It can be in quartz or schist or mica or other rocks. Often in or next to a very black vein. Any ideas?

 

[Red James Cash]

The two middle pictures are of small red crystals,not stains.

 

[loco oro]

I would guess from pics hematite likely, bottom pic looks like siderite,often found with iron rich deposits