Back to cutting and pasting replies I see.

When the images started coming back from MER of the blueberries my first thought was maybe they were tektites. They have the shape I've seen in ones I've held. So it seemed a good bet they could be. But then we found them in material I then thought must be volcanic in nature so they could best be explained by accretion or concretion. Then JPL reported they were mostly hematite and they believed then to be concretions.

About that time Ed started writing they were tektites with no good explanation of how. So we as a Space Science community that he is posting to have a right to know his reasons behind this theory or he should stop posting it here.

Here is more on Earthly tektites:

Tektites are small pieces of glass ranging in size from sand grain-sized particles to isolated fragments weighing as much 1 kg (2 lb). Usually smoothly rounded in contour, they take the symmetrical forms of buttons, dumbbells, teardrops, disks, winged bodies, and rods (see figure). The glass, which may appear very dark, is colored green, brown, or amber. The shapes of tektites show clearly that they solidified from droplets free to adjust their outlines to surface tension. Moreover, they may show markings such as grooves and flanges, that suggest the effects of attrition by air resistance during their fall.

Most opinion seems to be in agreement that tektites solidified from liquid drops falling through the atmosphere. Hypotheses about the origins of tektites range from extra-terrestrial sources (likely lunar) to terrestrial origins. The lunar origin has been ruled out because of the dissimilar analyses of tektites and lunar rock samples. However, the terrestrial origin hypothesis is widely accepted. Melting occurred through the impact of large meteorites, producing craters from which surface material was thrown upward into the atmosphere in a molten state. The tektites were formed as these melted particles fell back through the atmosphere.

All tektite glasses are high in silica, which ranges from 70 per cent Si02 (Australasian tektites) to as high as 97.6 per cent Si02 (Libyan tektites). Aluminum oxide is the second ranking constituent, forming about 13 per cent of the Australasian tektites. Iron, magnesium, and calcium are important lesser constituents. Tektite glass is unique in having a very high melting point (higher than that of Pyrex glass) and a low coefficient of expansion. Tektite glass with its high silica content is not the same as any glass that might be produced by melting of a stony meteorite.

Areas with concentrations of tektites on the Earth's surface are known as strewnfields. There appear to be five large strewnfields. The biggest of these is the Australasian field, which includes southern Australia, the Philippine Islands, Indonesia, and parts of Indochina and China. There is no obvious crater attached to this strewnfield and a few authors have suggested that there might be many local, and much smaller, impacts that were responsible for this field. Extremely minute tektites, known as microtektites, have been found in deep-sea sediments from a broad area of the Indian Ocean, and also constitute a part of the single Australasian strewnfield. Recent studies are pointing toward a likely impact site or sites in Indochina, associated with layered tektites of the 'Muong Nong' type.

http://www.science.uwaterloo.ca/earth/waton/f9922.html