We will certainly take microfossil matrix in trade for matrix that we have on hand.
You can send in matrix from your location and receive matrix from multiple sites. The matrix you have to offer will determine how much matrix you will receive in trade. Processed matrix is worth much more than unprocessed matrix. We cannot take well lithified chunks in trade; it must be able to be broken down with water alone. Some types yield 1 gallon of prepped matrix for ever 2 gallons raw, some yield 1 gallon prepped for every 10 gallons raw. Value will depend on the rarity of the site, average yield, fossil content (type and quantity), and the preservation of the contained fossils.
We also Buy microfossil matrix, so please feel free to contact us if you have any bulk matrix to sell.