Jasper comes in all sorts of colors. I think that when one uses "jasper" as a term for a color, one's talking about the reddish-orange tone. What the Bible means by it, I don't know.
I stand corrected. You are right. Here are a few links:
Chemical Formula: SiO2
Mineral Name: Jasper
Color: Brick red to brownish red
Hardness: 6.5- 7.5
Specific Gravity: 2.6- 2.64
Jasper is a dark green, semi-translucent to opaque form of semiprecious chalcedony. It derives its name from the Greek iaspis. It owes its color to admixed hematite, but when it occurs with clay admixed, the color is a yellowish white or gray, or with goethite, a brown or yellow. Jasper is opaque, fine-grained or dense variety of the silica mineral chert. Jasper, long used for jewelry and ornamentation, has a dull luster but takes a fine polish. Its hardness and other physical properties are those of quartz.
http://www.semi-precious-stone.com/jasper-stone.html
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"And thou shalt set in it [the high-priest's breastplate] settings of stones, even four rows of stones: the first row shall be a sardius, a topaz, and a carbuncle: this shall be the first row. And the second row shall be an emerald, a sapphire, and a diamond. And the third row a ligure, an agate, and an amethyst. And the fourth row a beryl, and an onyx, and a jasper: they shall be set in gold in their enclosings" -- Exodus 28:17-20
"In Exodus 28, we read of these stones in the breastplate of the high priest. The Sardius (the blood-red) stone having to do with Reuben is mentioned first, and the Jasper stone last. Revelation 4 speaks first of the Jasper stone--the clear white stone of Benjamin. This is not to be taken lightly. There is a definite reason for reversing of the stones, putting the first last, and the last first.
"The Sardius was blood-red, speaking of the sacrifice of blood, pointing to the cross and the first coming of Jesus to shed His blood for the remission of sin. The name is derived from two Hebrew words meaning 'behold the Son.' It pointed to the person of whom John the Baptist said, 'Behold the Lamb of God which taketh away the sin of the world' (John 1:29). It also tells us that He (the Lord Jesus) was the first born of every creature, and the first begotten--the ONLY begotten--son of God (John 3:16).
"The Jasper, the last stone in the Old Testament breastplate, represented Benjamin. This was a clear stone, speaking of total victory. On the Jasper stone was Benjamin's name, which is a combination of two Hebrew words (BEN and JAMIN), so scholars tell us, meaning 'the son of my right hand'...or, as one authority puts it, 'the son of my power.' The first and last stones pointed forward to the first and second coming of the great High Priest--none other than the Lord Jesus Christ.
"However, here in Revelation 4, the order of the stones is reversed. John the Beloved sees Him (Jesus) first as the Jasper, and second as the Sardius. The reason is clear: In the Old Testament the saints looked forward to the day when the Lamb would come, they looked forward to the cross, and therefore saw the Sardius...the blood-red stone...first. They looked beyond that and saw the Jasper, the clear white stone representing His power and His rule at His second coming to set up the kingdom. However, when John had the experience we are now studying, he was on this side of Calvary and the Rapture, and was looking back. John saw, first of all, the Jasper stone, the clear one--and then the red stone, the cross and sacrifice."
http://philologos.org/bpr/files/j001.htm
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As for knowing what the Bible meant, I think we'll have to rely on Christian Dude and KK to tell us.
