Ranging From Somewhat Scientific to Eminently Esoteric
Abundance Crystal - A crystal point with smaller crystals growing around its base. These crystals foster prosperity and well-being, success, good fortune and all good things in life.
Activation Left Crystal (also called a Time-Link Crystal) - This crystal has an extra inclined facet located to the left of the main face of the crystal (looks like a parallelogram). These crystals are used to activate the right hemisphere of the brain. Some attributes are creativity, imagination, psychic ability, and meditation.
Activation Right Crystal (also called a Time-Link Crystal) - This crystal has an extra inclined facet located to the right of the main face of the crystal (looks like a parallelogram). These crystals are used to activate the left hemisphere of the brain. Attributes include logic, intellect, and action-orientation.
Artemis Crystal - See Candle Crystal.
Asterism - The effect of light rays forming a star, usually created through reflection of light by thin, fibrous or needle-like inclusions that lie in various directions within the mineral.
Aura Quartz Crystals - Clear quartz crystals that have first been heated in a vacuum to extremely hot temperatures, then electrically infused with other chemical(s), usually 24k gold and/or a combination of other chemical elements, to produce a permanently bonded color coating. These crystals are known by a variety of names, such as: Aqua Aura, Opal Aura, Copper Aura, Flame Aura, Titanium Aura, Angel Aura, Rose Aura, Aurora, Tanzine, and others. These specialty crystals are known as intense auric cleansers.
Barnacle Crystal - A crystal that is covered or partially covered with smaller crystals. These crystals can be used to stimulate group cohesiveness.
Bent Crystal - See Curved Crystal.
Bridge Crystal - Recognized by a smaller crystal which penetrates and is located partially in, and partially out of a larger crystal. It facilitates bridging between the inner and outer worlds and between self and others. This crystal can also be referred to as a Penetrator, a Trigger, or an Inner Child Crystal.
Burr - A crystal cluster with point terminations radiating out in every direction, not just up and out (like a haystack of sorts). High quality large specimens are rare.
Cactus Quartz - A crystal that has grown so quickly in the long direction that the end faces are not filled in on the crystal aggregates to form a "single" crystal. Tiny faces terminate each point, all in the same orientation. Often called Spirit Quartz, the effect is of a cactus with stickers going out in all directions.
Candle Crystal - A long crystal with a sharp, undamaged point, resembling an arrow (ratio of 6 to 1 or greater, length to width). Also known as an Artemis or Diana, this crystal could also be considered just an elongated Generator Crystal. It is very supportive of those who are struggling for independence of all kinds.
Candle Quartz - This crystal is a type of elestial quartz, and appears as a candle would with wax dribbling down the side. It acts to induce sensitivity and prudence.
Cathedral Crystal - This term is used in several contexts:
In reference to clear quartz, a Cathedral is a crystal that has no upper dividing line between the facet and one of its sides (relatively rare, and often found as the opposite side of the receiver face of a Receiver Crystal). Another usage is that of an upright crystal with all of its facets resembling the spires and towers of a church cathedral. Amethyst Cathedrals (or Churches) are usually tall, thin geodes (again, resembling church towers) that have been cut to display the sacred inner sanctum of amethyst (and other) crystals.
Channeling Crystal - Also known as a Projector, this crystal that has a large seven-sided face located in the front center of the termination and a perfect triangle located on the back side. These crystals assist one in accessing innate wisdom and effectively communicating verbally.
Chatoyancy - Cat's-eye effect that resembles the slit eye of a cat and is caused by the reflection of light by parallel fibers, needles or channels. This phenomenon is most effective when the stone is cut en cabochon, as in cat's-eye quartz jewelry.
Chimney Crystal - A thin sheet-like piece of quartz that connects two larger points, usually lasers.
Chlorite-Included Crystal - Any crystal with chlorite inclusions. These crystals promote celestial contact with the highest order of angels.
Cluster - A group of single terminated crystals that share a common base. There may be hundreds of points, or only two, but they live together in an evolved community of peace and harmony. The auric light that surrounds a quartz cluster is very bright and strong, and will bathe an entire area or room in radiance.Comet Crystal - A crystal with a number of tiny crater-like indentations on one or more sides, ending in a spray trailing behind (like the tail of a comet). This crystal is a great aid to being in sync with the entire universe and seeing the "big picture".
Consumption Crystal - A rare form of quartz that appears as one crystal engulfing or consuming another. This crystal is a stone for progression and allows for a liberal flow of emotions.
Crater Crystal - A crystal that at one time had another crystal(s) attached to one of its sides. The missing crystal left behind a crater-like depression. These crystals symbolize our capacity to detach, let go, and continue on.
Creator Crystal - A larger crystal with a tiny completely formed crystal growing deep within. Creator Crystals remind us there is always a seed of creation available to us whenever we want to bring something new into our lives.
Cross Crystal - A formation of two crystals attached to each other in the shape of a cross. It is a world teacher, and an excellent stone for studying spirituality, and the arts and sciences.
Crystal - A solid mass of mineral, having a regular geometric shape and bounded by smooth, flat surfaces (crystal faces).
Crystallography - The study of crystals, including their growth, structure, physical properties, and classification by form.
Curved Crystal - A rare crystal formed in a bent or curved shape that emanates a gentle, but powerful energy that allows access to the interior of the physical body.
Dendritic Crystal - A crystal that contains branch-like inclusions which resemble a moss or plant form. It can facilitate closeness with nature, and also stimulate recall of past lives relative to this earth.
Devic Crystal - A crystal that contains multiple internal fractures and inclusions of trapped water, air and gases (often called wispy veils or fairy frost). These crystals can be any shape, formation, or size, and do not even have to have terminations. But they are a great aid to tuning into "nature spirits" and other beings of light.
Diana Crystal - See Candle Crystal.
Dolphin Crystal - A crystal that has a smaller, shorter crystal fastened along its side. Use these crystals to attune to the water dwellers of our planet, and to protect the young, the defenseless, the sensitive, the innocent.
Double Terminated Crystal - A crystal that has a single termination on each end. The energy flows in both directions at once, and can draw or transmit energy through both ends. These doubly powerful crystals are great for dreaming, meditation, and astral projection.
Dow Crystal - A crystal that has a termination with three perfect triangle facets, separated by three seven-sided facets. This versatile crystal represents near perfect balance, and can assist in just about all matters.
Drusy Quartz Crystal - A crystal dusted with an encrustation of minute projecting crystals, usually of the same material. Drusy Quartz is one of the best energy tools for working through any self-exploration
Earthkeeper Crystal - These crystals are buried deep within the earth, and can weigh several hundred pounds to several tons. They are the giants of the crystal clan, and most have not yet been located by humans.
Egg-Shaped Crystals - This shape, usually fabricated, is extremely versatile, and has been used in reflexology, zone-therapy, acupressure, shiatsu and aura reading.
8-Faceted Crystal - A rare crystal with eight faces (facets) instead of the normal six. This crystal is associated with prosperity, success and accomplishment, balancing a desire for material things with spiritual growth.
Elestial (or Elestiated) Crystal - This crystal, sometimes called Skeleton Quartz, has a smoky look and appears to have been burned by fire. The youngest form of quartz on earth, it is unlike any other form of quartz. Flowing terminations (usually not sharp) have formed over the faces and body of the crystal, and are usually tabular, rectangular or square, with rounded corners. Markings on the surface can have the appearance of cryptic hieroglyphics, a cosmic alphabet of sorts. Once you see one, you'll always recognize an Elestial!
Empathic Crystal - A crystal with damage. These crystals are considered unattractive, through no fault of their own, and can assist us in developing compassion for the suffering of others.
Enhanced (or Treated) Crystals - Crystals that have been put through a process to change or improve the crystal in some way, often affecting the color of the crystal.
Enhydro Crystal - A crystal included with bubbles or pockets containing fluid. Also known as a Level Crystal, this container of an ancient element helps us access physical time: past, present, future.
Etched Crystal - A crystal that has markings on the its surfaces, often resembling hieroglyphics.
Extra-Terrestrial (ET) Crystal - A crystal with a single termination on one end, and multiple terminations on the other end (looks like a rocket ship). These crystals can spray out energy and also take in large amounts of energy. Good choices for entrepreneurs, these crystals are exceptional energy rechargers and personal motivators.
Face (Facet) - A flat outer surface of a natural crystal, usually referring to the surfaces from the body to the termination. The words "facet" and "face" are commonly used interchangeably.
Faden-Line Crystal - This crystal has an inclusion of one or more white thread-like fibrous formations, possibly curved, and located near the center of the crystal. This crystal is rare, and facilitates attunement between self and others.
Female Crystal - A general reference to a crystal that reacts in a calm and rational way.
Fracture - Also known as a "foil", this is an interior breakage or splintering of crystal in no particular direction, often the source of beautiful reflective rainbow colors.
Generator Crystal - A crystal with all six faces meeting at the top termination in a near-perfect point. These powerful crystals generate and project energy, and are extraordinary meditation tools.
Geode - A rock opening, usually a round hollow created by gas bubbles in magmatic rock or spaces where organic material has been removed in sedimentary material. The nodules are lined with crystals, usually quartz or calcite. Amethyst is commonly seen in geode form.
Golden Healer - A quartz crystal with is partially or completely covered with a transparent golden yellow mineral, iron oxide. This crystal is an excellent stone in all healing situations.
Grounding Crystal - A rare crystal with eight sides surrounding the largest face. This is a moderately powerful crystal, used in very practical, down-to-earth matters.
Growth Lines - See Striated Crystal.
Gwindel Crystal - A cluster of double terminated tabular crystals that are stacked on tope of each other in a spiral or twisted formation.
Harlequin Crystal - A crystal included with red and silver specks and/or strings of hematite or lepidocrocite and titanium. Displaying great dancing energy, this type of crystal is a great provider of physical energy and vitality.
Herkimer Diamond - Not a diamond at all, this crystal is a small, barrel-shaped double terminated crystal found only in Herkimer County, New York. Exceptionally clear, these crystals are the power horses of the crystal clan, no matter the size, and true Herkimers are becoming difficult to find in the marketplace.
Included (Inclusion) Quartz - Quartz that has any of the following included within its interior: foreign particle or mineral, organic inclusion, liquid or gas, irregularity in the crystal lattice, color striations, breaks and splits. Inclusions are usually not considered "flaws", but rather individual character traits that give each crystal its unique identity.
Inner Child Crystal - A crystal partially embedded in another crystal or a smaller crystal cradled between two parent crystals. Protect the child in you!
Irradiated Crystal - A crystal that has been subjected to bombardment by atomic energy. This treatment/enhancement is usually done to improve the intensity of color, such as in smoky quartz and blue topaz.
Isis Crystal - Any crystal with one large face surrounded by five sides. The sides are arranged in the shape of the symbol of the Egyptian goddess Isis. These crystals strongly amplify feminine energy and are powerful healing crystals.
Jacare Crystal - A form of Elestial Quartz
Japanese Twin (or Japan Law Twin) Crystal - A crystal in which two single crystals, usually broad flattened prisms, (and one a penetration twin), are joined in the same plane at an angle of about 84 degrees. This is an excellent crystal for clearing the auric field.
Key Crystal - A crystal recognized by a three or six-sided indentation that gets narrower as it enters (and ends within) the crystal. What doors would you like to unlock?
Laser Crystal - A long, slender crystal that tapers to a small, sharp termination. Sides are frequently uneven, some are etched, and they have a slightly ancient, "used" look. The energy of this wand is well focused in the small tip, and the use of a laser wand during meditation establishes finer communication between other worlds.
Left-Handed Crystal - A quartz crystal with an extra face on the left side of the largest face. This means that the crystal spiral within the crystal itself flows naturally to the left. This crystal is naturally most receptive to incoming energy when held in the left hand or held on left side of the body.
Lens Quartz - See Sheet Quartz.
Level Crystal - See Enhydro Crystal.
Library Crystal - A crystal that has many newer, flat, stubby crystals attached to the outside surface of the larger crystal. These are overgrowths, and often resemble a thick layer of plaster. This crystal is a carrier of many volumes of information, a kin to the Record Keeper Crystal.
Life Path Crystal - A long, thin crystal with one or more totally smooth sides. If you are fortunate enough to find one, it will make an excellent meditation and spiritual exercise tool to keep you on your path.
Male Crystal - A general term for any clear crystal that acts in a speedy, straight-forward manner.
Manifestation Crystal - A rare crystal that has another crystal totally enclosed within it. This crystal is a superb manifestation tool for the person with a clear inner knowledge of his/her inner self.
Master Channeling Crystal - A rare crystal with seven facets instead of five or six. This is not the same as a Channeling Crystal that has seven lines defining the facets. These seven facets represent the mystic student, the spiritual seeker. This crystal will help you receive information from your teaching masters.
Master Matrix Crystal - A crystal with most, if not all, of the known geometric shapes etched naturally on the outside (or inside) of the crystal. This crystal is a master programmer used to recharge, expand, or reboot Record Keeper Crystals. Although not usually beautiful crystals, these gems are extremely rare.
Matrix - The host rock in which a crystal is embedded.
Mineral - A naturally occurring, inorganic, solid constituent of the earth's (or other celestial body's) crust. Most minerals have definite chemical compositions and crystal structures.
Muse Crystal - A cluster with nine similarly sized crystals which represent the nine Greek goddesses who preside over the arts. This crystal enhances all forms of creative expression.
Mythic Crystal - A milky quartz (or snow quartz), double terminated and opaque. This crystal is used to track both the earth's history and personal history, backward and forward.
Needle Crystal - A long, clear, extremely thin and narrow crystal, four times as long as wide. Although fragile, this crystal is used to direct energy movement with precision, and is often used in alternative healing processes.
Numerological Crystal - Any quartz crystal with clearly defined facets. Count the lines that create the outline of each face (count each only once), add them up. Then add those two digits together to get the master number to which the crystal resonates.
Osiris Crystal - Any dark smoky quartz Generator Crystal that is a natural smoky, not one created by irradiation. The Egyptian Lord Osiris was a symbol representing the higher self, and this crystal will help you succeed in the physical world.
Overcoat Quartz - A crystal with a creamy white layer of milky quartz that has formed a heavy coating over clear quartz.
Parity Crystal - This is a cluster of any number of identically sized crystals, reminding us that we are all peers on a spiritual level.
Penetrator Crystal - Any crystal that partially penetrates another. This crystal is a great motivator to help us plow ahead when we would rather not!
Phantom Crystal - A crystal containing the growth outline, or image, of another crystal inside. The phantom is comprised of a white or colored mineral, partial or complete, and often appearing very wispy and ghost-like. This crystal is a reminder that we, too, can grow beyond our expectations, and are protected during times of new growth.
Picture Window Crystal - A slightly rounded and egg-shaped quartz that has been tumbled (originally a natural process occurring in the riverbeds of Brazil). This tumbling gives the crystal its characteristic frosty exterior. One end has been sliced off and polished to allow a window deep into the interior. This is a powerful meditation tool and very effective Shaman stone.
Point - Refers to a single crystal with one termination.
Projector Crystal - See Channeling Crystal and Generator Crystal.
Quantum Crystal - A cluster of three or more quartz crystals of equal or nearly equal size and length, naturally joined together. This crystal has the power to influence what quantum physics currently calls "probability waves", which is exceptionally useful in helping alter the probable statistical outcome of any situation.
Rainbow Crystal - Any crystal with internal fractures (foils) that flash colors when turned in the light. These crystals are natural promoters of happiness, hope, optimism, peace, courage, creativity. Rainbow crystals are master depression fighters.
Receiver Crystal - A crystal with one broad, upward-sloping face. These crystals are great receivers of energy and dreams, and make a great companion for a Generator Crystal.
Receiver-Generator Crystal - Any Generator Crystal with one face that slopes inward more than the other five faces (unlike a true Generator that has six equidistant faces). These crystals simultaneously receive and project energy, and are considered great multi-functional tools.
Recorder Crystal - See Record Keeper Crystal.
Record Keeper Crystal - A crystal with a geometric figure (usually a triangle) naturally etched into one or more of its faces. These figures will often appear after awhile, even if they were invisible at first inspection. Wisdom is contained in these crystals, programmed by psychic beings and their descendants, such as the Atlanteans and Lemurians. It is said that only those with open minds and pure hearts can attune to the information held therein.
Right-Handed Crystal - A crystal with an extra face on the right side of the largest face. Here, the energy flows naturally to the right. These crystals are excellent tools for any activity requiring intellectual or analytical abilities, and make good companion crystals for the Left-Handed Crystal.
Rock - With regard to gems, a rock is a natural aggregate of two or more minerals.
Rock Crystal - Another name for clear quartz crystal.
Rutilated Crystal - Quartz that is included with hair-like needles, usually golden yellow or red in color. These "hairs", are usually straight and composed of rutile, goethite or sagenite. Very beautiful, rutilated quartz can assist in getting to the root of any problem.
Scanner Crystal - A crystal with one or more wide flat sides (usually not a Tabby, but it could be). Scanners are not particularly beautiful, but can be used to scan the energy of just about anything.
Scepter Crystal - A crystal with an overgrowth capping its terminated point - a royal scepter look. Symbolizing sovereignty and authority, these crystals directly link several chakras, transmit directional energy, and represent all sky deities.
Scrubber Crystal - A crystal cluster whose points are all even and nearly equal in length. A scrubber is beneficial in scrubbing down the energy around you, especially when surrounded by negative energy or illness.
Selene Crystal - A crystal that contains a rounded inner inclusion, reminiscent of any phase of the moon. Named for Selene, ancient goddess of the moon, a Selene Crystal is soothing, calming, and a great psychic stimulator.
Seer Stone - See Picture Window Crystal.
Self-Healed Crystal - A crystal that was broken or split from its matrix base while still in the earth. It then rehealed by growing one or more terminations over the broken area. This crystal is an excellent choice for any type of healing.
7-Faceted Crystal - See Master Channeling Crystal.
Shaman Dow Crystal - A Dow crystal that also contains a white phantom. This phantom represents a template of the individual soul.
Shard Crystal - A crystal that is broad, flat, and layered in a plate-like mass rather than in the usual six-sided hexagonal crystal. Shards can also be pieces of quartz, and come in all sizes and shapes. They share many properties of the Self-Healed Crystal, and assist us in dreaming and transforming our lives.
Sheet Quartz - Crystals that form in flat layers. Also called Lens Quartz, this quartz provides windows to other dimensions.
Shovel Crystal - A crystal with one long shovel-shaped face. This quartz helps us gather knowledge throughout our travels and find solutions when needed. The Shovel Crystal differs from a Spade Quartz in that the main face is longer than that of a Spade.
Singing Crystal - A crystal similar to a Laser Crystal, but normally smaller. Touched by another Singing Crystal, a beautiful sound resonates and is said to create the powerful "OM" vibration, stimulating our creative forces.
Skeletal Quartz - See Elestial Quartz.
Smelted Quartz - This quartz has been refashioned by a man-made process of melting raw, natural quartz at high temperatures, mixing in a few additives (copper, for one), then cooling and shaping it into its new form (spheres are a common choice). Resulting crystals are frequently of high clarity, and often contain beautiful fluffy, cloud-like inclusions. Not-so-beautiful quartz is given this wonderful opportunity to become more than it could ever be on its own, resulting in beautiful art pieces to be treasured forever.
Soul Mate Crystal - See Twin Crystals.
Spade Crystal - This quartz has a face that is shaped much like a spade in a deck of cards. Similar to a Shovel Crystal, the spade facet is shorter on this quartz. Use this one for astral travel!
Spiral Crystal - A crystal that is twisted through the body. This crystal has been used to activate the movement of kundalini energy through the chakra centers of the physical body.
Spirit Guardian Crystal - Two Double Terminated Crystals of equal or nearly equal size and length, growing side-by-side. These crystals are a reminder that we are never alone, and facilitate our connection with spirit guardians, guides and teachers in other dimensions.
Spirit Quartz - A crystal often called Cactus Quartz because it appears as a cactus cluster with stickers or spires sticking out. These crystals can be found on both clear and amethyst quartz clusters (the amethyst clusters usually display a lavender color rather than deep purple). Spirit Quartz can be used to strengthen group cohesiveness, generate energy, and assist one when experiencing loss.
Striated Quartz - A crystal with shallow, parallel grooves on the side or face surfaces, sometimes referred to as growth lines.
Tabular Crystal- A crystal that is flat, with two of its six sides being at least twice as wide as the others. Also known as Tabbies, these special crystals emit a very high vibration and are not found in all mines. Tabbies are strong, powerful connecting communicators, and are excellent tools for bridging any gaps. Tabular Crystals often become personal meditation pieces or private teacher crystals.
Tangerine Quartz - A crystal coated with an orangish tangerine-colored material that is not removed in the usual acid baths. This crystal is commonly used to promote Inner Self evaluation and evolution.
Tantric Twin Crystal - See Japanese Twin Crystal.
Teacher Crystal - A crystal containing the shadow of a shape or form (human or otherwise). These forms are symbolic, personal to the individual using the crystal, and can appear in any other type of crystal personality.
Time-Link Crystal - A crystal with a parallelogram as one of its faces (usually much smaller than the other faces). If the parallelogram leans to the left, it supports you in achieving your goals. If it leans to the right, it is a great tool for sparking your natural inspiration and creativity. Trace the evolution of your essence throughout physical "time".
Toning Crystal - A crystal that is most often found as a long, thin, perfectly clear crystal, single or double terminated, with most angles at right angles to one another. Unlike the "used" look of Laser Crystals, Toning Crystals almost appear to be man-made. These crystals are used to intensify, amplify and store sound.
Transformation Crystal - A crystal of any configuration. It won't be recognized until a change actually occurs in the crystal itself, such as its shape, quality, and/or color. This crystal assists one in forward movement in all aspects of life.
Transmitter Crystal - A crystal with two symmetrical seven-sided faces on both sides of a three-sided triangular face. The triangle will always be in the center of the crystal's faces, with a seven-sided face on either side of it. Transmitters are often Record Keepers as well, and are outstanding tools for sending and receiving telepathic messages.
Treated Crystal - See Enhanced Crystal.
Trigger Crystal - A crystal with a smaller crystal on one of its sides, near the base (although it can be further up the side). Triggers can occur in any crystal personality, and they allow for short, intense bursts of energy directed to the target of your choice!
Trigonic Crystal - A crystal with many small triangles on the termination faces, pointing in both directions. Unlike Record Keepers with their perfect equilateral triangles, these triangles appear wavelike, with many overlapping each other.
Twin Crystal - A crystal that has grown together with another (Contact Twin) or intergrown with another (Penetration Twin) in such a way that parts of each crystal are in parallel alignment and parts of each crystal are in reverse position in relation to the other.
Also called Soul Mate Crystals, they are nearly equal in size and length, and assist in the building of relationships at all levels.
Twin Flame Crystal - Two crystals that are either joined at the base in a V-shaped formation or at their sides. They are similar crystals, but not the same size or length. These crystals help us attract kindred souls on a platonic level rather than on a romantic one.
Veil (Wispy Veil) Crystal - A crystal containing thin, wispy veils inside. Sometimes called Fairy Frost, these veils can appear like silver foils or mirrors, and often reflect prismatic colors. Veil Crystals are outstanding meditation tools, especially when two sides of an issue are involved.
Wall Crystal - A crystal with a veil stretching completely across, dividing it into two sections. This type of crystal is used when simultaneous access to past, present and future is needed.
Wand Crystal - A long slender crystal tapered to a sharp termination, usually longer than three inches. It carries the same capabilities as the Laser Wand, but may not have the same etched appearance.
Warrior Crystal - A crystal (most often a Generator, Laser or Quantum) that has damaged, chipped or broken points. Warrior Crystals often display gorgeous rainbows, reminding us to overcome our "damage" and shine our lights as they do. These power pieces make great vision quest tools.
Window Crystal - A crystal that has a perfect diamond shape in the center front of its faces, large enough to easily peer into. The corners point to the four directions, and often make up the seventh face of a crystal (see 7-Faceted Crystal). Use a Window Crystal in meditation to gaze into your inner nature.
X Crystal - Two crystals that have grown together naturally to form an X. These crystals have the special ability to bring female/male energies into harmony, and can be used when a well-balanced decision is needed.
Y Crystal - Two crystals that have grown together naturally to form the letter Y. A great companion piece to the X Crystal, these crystals balance female/male energies and are good tools for developing natural intuition and telepathy.
Most of the above information and much more can be found in the following fabulous books:
The Audubon Society Field Guide to North American Rocks and Minerals, Alfred Knopf Collecting Crystals: The Guide to Quartz in Arkansas, Darcy and Mike Howard
Crystal Enlightenment, Katrina Raphaell
Crystal Personalities, Patricia Troyer
Gem Magic, Brenda Knight
Gemstones of the World, Walter Schumann
Love Is In The Earth, Melody
Love Is In The Earth Pictorial, Supplement A, Melody
Love Is In The Earth Mineralogical Pictorial, Melody
All can be purchased at www.amazon.com