Cannabinoids are generally that color, some strains produce darker oil, but in general if it spreads green like that it most likely has a fair bit of chlorophyll. The oil may have been made with sugar trim and not buds. From what I've noticed the more quality goes in the "better" it looks. Look at the stuff that TerpX and those crews are putting out, nothing but clear see-through shatters.
That's not to say that dark oil automatically equals bad oil, but I think it's a decent indicator of what material it was made out of. I see they're priced pretty cheap, is all the oil like that in Oakland? I'm down in San Diego where 40-60 a gram is common but I saw some dark green Sour Diesel oil up in Los Angeles for $20 a gram. Went with the honeycomb Blue Dream at double the price per gram.
Sorry it took me so long to respond there, Quetzalcoatl, got kinda scattered around here. Thanks for the info. Kinda what I figured, better starting material = better concentrate, all processes being equal and clean.
To answer your ?, there is A LOT of crap oil here in Oakland, I swear it is the dumping ground for some of the worst commercial BHO and iso, but true, there is some good stuff too. Now, mind you, I do not mind paying cheap prices for oils of cheaper strains, but the oil or concentrate itself must be made well.
Like you, I believe that if you can afford it, a Blue Dream CO2 wax, say, would be worth twice the price of a $20 bottle of BHO.
Once in a while, I come across a good oil that both tastes like the strain it comes from, may be yellow or orange or amber but never brown or dark, and that is usually my fav. The totally clear concentrate stuff is just stripped of all flavor, for my taste.