Are these diamonds? What are some tests to perform? I've already done the sapphire test. The bigger ones scratched the sapphire, The smaller ones were to small to try. The small ones are in the shape of octahedrons.
I really can't tell from the pic and any pics really need to be taken in natural light to show off the true shine of Diamonds! I will say, if some or all have the appearance of the dull side of Aluminum Foil in person, then it is a good chance that any with this appearance are actual Diamonds. The one thing working against them from being natural White Diamonds, is the fact that there is really only one place in the U.S. that is known for high quality White Diamonds and that is the Crater of Diamonds State Park In Murfreesboro, Arkansas. The Lamproite (Volcanic) Pipe (formerly thought to be a Kimberlite Pipe) there has produced higher quality Diamonds than practically any other location on Earth and in Whites, Yellows, Champagnes and Browns.
I do not have a 10x loupe, and I did not find these rockhounding. I found them in my collection of rocks. (Which is very big). So I don't have a clue as to where they came from. I have a macro lens for my nikon, I will try to get a close up in natural light to show you guys.
You could take them to a jewelry store to be tested or a gem and mineral society. The Gem and Mineral Society of Texas will test them and certify them for $5.00 for each uncut stone or $79.99 for each facted stone. Hope this helps.