Indian artifacts can be found in many contexts. On rare occasions I have found isolated stone tools in places that appear to be otherwise void of any other artifact of any type. I imagine that these might possibly be objects lost during a hunt, though that is only speculation. Far more often, arrowheads and other tools are found at sites where Indians actually lived, right where their dwellings were erected at one time. In these places they cooked and ate and slept, they worked and played games, raised their children, and they also made and maintained stone tools. This created a lot of debitage in the form of chips and flakes of toolmaking stone. Today, these chips and flakes are, in most places, the most obvious signs of prehistoric occupation. When I am in a new spot I look not for tools but for these broken flakes. When I find chips and flakes, I know there are likely to be tools there as well, and that is when I start looking most thoroughly and carefully.
To identify debitage it is helpful to know how stones are broken by nature and how that is different from rocks broken by a person. I am going to make some general comments, please note that there are exceptions to every rule and different settings and circumstances can produce different results. I am not a geologist and base this on my study of archaeological site reports and also my experience looking at thousands of rocks in places where I find artifacts and also in places where I don't find anything. Some types of rock are soft and frangible and these could perhaps be broken by frost or other natural processes but the types of stone used by Indians for tools were generally hard and not likely to be easily broken. Quartz is a type of stone that is very hard and was generally widely used by prehistoric people in what is now Massachusetts. In some places it was used more than in others, and some cultures had a strong preference for other materials, but quartz tools are found at nearly all sites in southern New England where Indian artifacts have been recovered, and some archaeological reports go as far as calling quartz debitage "ubiquitous" at these sites. Quartz breaks unpredictably and I believe that attempting to make quartz tools produces a lot of debitage for every finished point so there is a lot of it around. In dirt and gravel, and in and around waterways, quartz is usually found in the form of round pebbles and cobbles. These pebbles can be broken by glacial action and sometimes by moving around in water. When this happens, usually the pebble is broken, it tumbles around and the broken piece becomes more or less worn, and then it is broken again, and so on, producing a rock with breaks showing varying degrees of wear. If you find quartz pieces on the ground that have multiple broken faces all of which show no appreciable wear, especially when no part of the original smooth outer surface of the pebble remains, you are probably looking at something broken by a person. Quartz often does not break conchoidally and it generally does not show flaking so looking for a bulb of percussion or concave flaking is not really helpful when evaluating broken pieces of this material. In my experience if you find an area with multiple small broken quartz pieces that include flat sharp flakes and jagged broken chunks, and you can rule out crushed stone/gravel laid down in recent times and rocks broken by vehicles, you have found a prehistoric site.
When I find a site I will pick up the debitage and take it home. I do this to keep the entire artifact assemblage intact for possible future archaeologists who may want to study these sites. I also like to study the flaking and materials. Sometimes I go through my piles of debitage sorted by site and I find broken tools I did not recognize at first. Also, I don't want other arrowhead hunters to come by and see this stuff and find my spots. Last night I spent a little while in a sandy place, here are the flakes I brought home.
Last week on Wednesday I searched a spot where I have had some luck this summer. I found a lot of chips and flakes before I ever found a tool in this place. I was pleased to spot this sticking out of the dirt: