Any chance that you could have found it where there was a fire? It looks a lot like the blobs of aluminum from melted cans, a fairly common find around campgrounds, on beaches, etc.
What you have there looks like ferrochrome a naturally occuring form of chrome, I'm just guessing from the picture, to be sure I'd have to check the weight and hardness. If you prospect the Llano River near Kingsland Texas you will find veins of it in the granite, and some loose specimines in the river.
The second picture is A specimen of rich ("bonanza-grade") silver ore from Fresnillo in Zacatecas state, north-central Mexico. Sample 061, collected from an active stope on the steeply-dipping, strongly-banded ore of the Santo Niño vein, 10 m above the 425 level of the Fresnillo mine, on 29 September 1981. As you can see it isn't shiny.