Little wonder then that aqua-colored crystals in a pegmatite at Halibut Point piqued my curiosity and possessiveness. They spark the imaginations of children. They are delightful.
In pursuit of some factual information I contacted Professor Ross of Northeastern University who suggested a test to support his hunch that the photo and circumstances pointed to fluorite, a mineral with a hardness rating of 4 (H=4.) If so, a penny (H=3) shouldn't scratch it but window glass (H=5) should. I was pleased to assemble a geology field kit so easily, and proceeded with the test. The aqua crystals withstood the penny but not the glass. The evidence affirmed fluorite (CaF2) as the spark among the granite grays.
Several years ago I began to consider how color and light might enhance my stone carvings. I came across a heavy-duty stained glass whose thickness produced rich colors and combined well with the architecture of granite.
|Kokomo Opalescent Glass|
Glass recipes involve melting ground-up mineral combinations that look like sand. Wagon-loads of mixtures waited in the store room of the plant.
The heart of the operation is the furnace, paralleling the igneous core of the earth. The time and expense necessary to get it hot enough to melt the glass silicates means that the furnace runs twenty-four hours a day. The business originally started in Kokomo because nearby gas fields at that time could supply abundant fuel.
At just the right consistency workers put the molten glass into molds where a twenty-four hour period of gradual cooling allows it to anneal, or organize its molecules for strength. The ability to produce inch-thick glass that anneals without shrinking or cracking requires rare skill. Different colors, made from different chemical compositions, vary in their annealing success rates.
I couldn't wait to get started when the first shipment of
slabs (dalles de verre) arrived from
Kokomo. It launched a series of adventures and challenges with glass and stone.
|Dalles de verre|
I wanted to explore the sense of glass emerging from stone, transparency from solidity, variegation from gray. Interestingly both the granite and the glass 'began life' as molten silicates.
Then it was time to move inside the stone itself, to devise techniques that could lead to internally illuminated lanterns.
The fiery origins of both granite and glass reminded me of a
brilliant celestial object. "Comet" glows both night and day.
"Lighthouse," six feet tall, ornaments a shoreline residence along the Ipswich Bay with illuminated panels on each of its four faces.
The emergence of light and color from these massive stones suggests a mysterious interior life, a curious trick, an improbability made believable. It's a hard-won playful pursuit of objects of delight.