Boulders of various sizes are routinely sold by gravel pits, material suppliers, and landscapers. So yes, boulders of milky quartz have value.
Yes
DEPOSITION
quartz
Basalt is a very abundant volcanic rock. A basalt boulder is simply a large chunk of basalt rock.
Quartzite is a metamorphic rock that forms when sandstone (which is composed largely of quartz) is subjected to high heat and pressure without undergoing melting. Since it is composed primarily of quartz, it shares the properties of quartz, such as high hardness.
The debris of boulders eroded and carried down by glaciers will eventually form moraines (mounds) where the front of the glacier melts and retreats, leaving the debris behind. Moraines can be high and wide enough to form a dam, behind which glacial melt water is trapped and lakes are formed.
Till looks like anything from fine rock, to large boulders in a cluster in which are picked up and carried by a glacier
Till looks like anything from fine rock, to large boulders in a cluster in which are picked up and carried by a glacier
Large boulders and smaller rocks can be carried by a river. When rocks and sediment are displaced, it's called erosion.
Mechanical weathering
Large boulders fell on highway 40 near Asheville, NC, causing traffic to come to a standstill. It will take several weeks to clear the boulders from the highway. Local residents must use secondary road 332 to get around Big High Mountain. There were boulders in every shape and size everywhere.
DEPOSITION
Quartz
quartz
Lemon quartz is a large crystalline quartz wherein individual crystals are distinguishable with the naked eye. Its transparent to translucent yellow color comes from iron.
Erratic blocks or "erratics" for short.
You are possibly thinking of the Moeraki Boulders, on the coast about 50km north of Dunedin. These are spherical concretions up to 1.5m diameter, naturally growing in clays derived from volcanic ash. Still quietly emerging as the coast erodes. In the mountains, giant boulders are frequently found, and some are huge. The biv rock in the Upper Arawhata is several tens of metres lin each dimension. In the Troyte, a small valley off the Karangarua, (Westland) the boulders may even be seen in satellite photos! These are all ex-glacial erratics.
Quartz is the most abundant single mineral in the crust, so it is not of particular value unless a specimen is unusually attractive or large.