Hi Peter Granite comes in all colors including black. (I know this to be a fact because I just installed black granite countertops in my kitchen). Also, even though granite has a reputation for being very resistant, it is succeptable to fracturing. I have seen granite boulders and headstones crack when left in the sun. Perhaps because the stone was black, it absorbed more heat than a light colored stone would. The high temperature differential between the light & dark sides of the sphere could lead to different expansion rates causing craking.
John John L. Carmichael Jr. Sundial Sculptures 925 E. Foothills Dr. Tucson Arizona 85718 USA Tel: 520-696-1709 Email: [EMAIL PROTECTED] Website: <http://www.sundialsculptures.com> ----- Original Message ----- From: "Peter Tandy" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Wednesday, April 03, 2002 3:24 AM Subject: Re: Fw: Sundial E-Mail Protest > Luke colletti wrote: > > The missing sphere was made of granite, > >was 7 feet in diameter and weighed 15 tons! The sphere was installed in > >1912 and was removed (due to its deteriorating condition - crack(s)) in > >1947. > > I would have to question, from the photos, that this sphere was granite, > sensu stricto. Granite is a light coloured acidic plutonic rock, and this > sphere looks very dark. I also wonder why it started cracking; granite is a > very resistant rock. Is there any information on just where the material > for the sphere was quarried? For the past 4-5 years there has been a small > market (I assume it's small) for large decorative rock spheres (granite, > marble, larvikite - which has a nice iridescence in the feldspar crystals, > sodalite - a delicate pale-blue colour, etc) mounted in a hollowed block of > the same, and supported by a thin film of water. They are thus rotatable in > all directions, and by hand no less! It's a strange feeling to change the > direction of such a heavy piece by hand presure alone. I've seen them up to > about 4 feet diameter (but usually smaller), but I agree, a 7 foot diameter > solid sphere would pose problems. But if only for the replacement of such a > large sphere of solid rock (which may be the largest anywhere?), it's > surely worth doing. > > Peter Tandy > > - > -
