Sample No.: HOW88401

Location: Mt. Howe

Dimensions (cm): 15x13x7.5

Field Number: 4094

Weight (g): 1622.7

Meteorite Type: Monomict Eucrite

Macroscopic Description: Roberta Score

Thin, black, shiny fusion crust covers 35% of this eucrite. Areas devoid of fusion crust are medium gray in color. Large areas of brown oxidation are present on the exterior surfaces. Material has been plucked out by physical abrasion, leaving large vugs that are typical of the Antarctic eucrites.

A large eucritic clast (7.5 x 6 x 1 cm) is exposed on an exterior surface which has no fusion crust. Oxidation stains part of this clast. A weathering rind extends several millimeters into the interior. Freshly exposed surfaces are lighter in color. Several smaller eucritic clasts were evident when the meteorite was chipped. Although the sample is coherent, abundant minute interior fractures cause the stone to break into smaller than desired chips.

Thin Section (,7) Description: Brian Mason

The section shows a microbreccia consisting of several coarsely crystalline clasts in a fine-grained matrix of comminuted plagioclase and pyroxene. The clasts range up to 3 mm across, and are generally of gabbroic texture, consisting of subhedral plagioclase and pyroxene grains. Microprobe analyses show pyroxene compositions ranging fairly continuously from Wo2Fs57 to Wo43Fs25, the range in En content being quite limited (En31-41). Plagioclase compositions are in the range An88-93. One grain of a silica polymorph, probably tridymite, was analysed. The meteorite is a monomict eucrite.