STONE SHOPPING

Taxonomy of Stoniness: A catalogue of stone collection

After spending a good 2 hour walk down at milford beach, I collected a vast sample size of stones for our task. Whilst searching for stones, I generally looked for interesting textures and colours that could be unique to use for materials in design. I found that during my search, 2 stones might look very different but are fundamentally from the same "family", due to weathering and erosion.

This is supposedly a work in progress taxonomy of stone that could relate to our design, however, this might not seem relevant due to our design proposal likely being constructed out of steel. Nonetheless, lessons can be learned from the classification of stone, or what the stone can represent.

The cover of the taxonomy presents 3 main family that rocks can break down into. Red refers to igneous, Yellow, sedimentary and the blue/black metamorphic.

Note: each stone was photographed from the same perspective and angle, hence the size of each stone should be in scale when compared to each other. The naming of each stone is non-logical and purely random based on visual relevance. I.e A range will cover mostly porous, igneous rocks etc.

CATALOGUE OF STONE

The taxonomy begins with Igneous as Daniel classifies: typically fine grained, hard rocks.

Our sample seems to be quite consistent with basalt and rhyolite.

Out of all the stones, our sample group with igneous was the largest. This was probably because the stones were sourced at Milford beach which had Rangitoto Island in its vicinity. Hence basalt and rhyolite rocks were quite common.

Basalt is a dark-colored, fine-grained, igneous rock composed mainly of plagioclase and pyroxene minerals. It most commonly forms as an extrusive rock, such as a lava flow, but can also form in small intrusive bodies, such as an igneous dike or a thin sill. It has a composition similar to gabbro.

Rhyolite is an igneous, volcanic rock, of felsic composition. It may have any texture from glassy to aphanitic to porphyritic. The mineral assemblage is usually quartz, sanidine and plagioclase. Biotite and hornblende are common accessory minerals. It is the extrusive equivalent to granite.

Image below presents all the igneous rocks within our sample group.

Note: would be good moving forward to accompany image with name tag.

From the bigger umbrella of Igneous, our sample family breaks into porous and solid, as Daniel notes: Basalt samples were commonly scoria due to its porosity.

Scoria is a type of igneous rock formed under pressure during the formation of volcanic cones. It is therefore extremely hard and durable yet very porous, so it drains water from surface soils extremely well.

Our sample group consisted of red basalt rocks, which made it difficult to identify between igneous or a sedimentary sandstone.

As mentioned before, the weathering effect/erosion made the appearance of stone quite deceiving from its core minerals.

Next on the taxonomy breaks Igenous rocks into two groups, hard and soft.

Pumice, called pumicite in its powdered or dust form, is a volcanic rock that consists of highly vesicular rough textured volcanic glass, which may or may not contain crystals. It is typically light colored

Aside from the hard basalt rocks, pumice rocks were found to be quite soft. From my experience with cutting the stones up with the watersaw, the pumice rocks turned into mud on contact with water and broke apart immediately. However, after drying up, the rocks would become rigid again.

The next big umbrella that we covered was sedimentary rocks, which mainly consisted of greywacke and sandstone.

Greywacke or graywacke (German grauwacke, signifying a grey, earthy rock) is a variety of sandstone generally characterized by its hardness, dark color, and poorly sorted angular grains of quartz, feldspar, and small rock fragments or lithic fragments set in a compact, clay-fine matrix.

There was an outlier piece as Daniel notes: a conglomerate piece which is a mixture of cement/mortar with basalt?

In comparison to Igneous, I found the Sedimentary rock, especially the big piece, second from the top left on the image below to be quite solid. The rock was very dense, and took a while before the saw would cut through the piece as compared to the porous igneous pieces. From our sample group, that particular piece was the most solid out of all our stones.

Whilst the sedimentary group had the hardest rock of all, the red sandstone pieces had the same problem with pumice, where the pieces would dissipate under contact with water.

A taxonomy based on colour, where Daniel notes: greywacke and certain sandstones where dark, and the rest neutral or light coloured.

The sandstones were quite dense and definitely weren't porous hence most of our collection fell into the solid section. The conglomerate piece is a mixture of basalt and cement, so it was categorised in the middle.

In our vast sample size, metamorphic rocks was definitely the rarest of the bunch. The only reason why we had a metamorphic rock in our sample group was because my neighbour had a nice garden with pretty rocks. (hope he didn't realise he was missing one or two)

I took closer shots of each rocks to look at the textures and composition of different rocks. We had ideas to further develop our taxonomy, the intention was to revisit the taxonomy over time and add to it. However, the design seems to have developed away from the stone side of things, and that will be it for the taxonomy for now.

Note: porous texture belonged to scoria, igneous rocks, the veiny looking ones were part of the sandstone sedimentary collection. Composite rocks were the conglomerates, consisting of both basalt and cement/mortar.

The colours of each rock is very rich and full of texture, the effects of erosion and weathering added a nice touch to these rocks.

I've also cut up pieces of each rock that reveals the inside of it, the watersaw also cleans up the edges and turns the rough surface into a matte smooth texture. I had plans to document it, but I guess we never got round to doing so. But, we did manage to use the piece to construct our stone massing models.

Stone textures

Taxonomy to be updated with future stone collection/ additional umbrellas to be put under